Evolution of the iNdoor design, part 2

At the same time that I was using CAD to draft the detailed layout design I also maintained a written description of the purpose of each section of the layout. I archived these descriptions, by date, so they are now useful in reconstructing how the layout evolved.

During the winter and spring of 2006 I worked on the layout design almost every day. My last post showed the layout design as of February 27. By March 3 I had updated a portion of the lower deck design as shown here:


Compared to the diagram in the last post, one difference that is immediately noticable is that there are now text labels for parts of the layout. I would expand on this practice over time with more labels and detailed descriptions within the CAD drawing.

You may note that the E-W main line was labeled "BNSF" and the N-S main line was "CN (Canadian National). The designation of the N-S line has varied over time as the layout concept has evolved. I like the CN railroad, and the layout will definitely feature it, but my current thinking is that the N-S line is owned by the SAMR (municipal railway), with trackage rights for every railroad that services the metro area. Similar to Chicago's Belt Railway.

Looking at the above diagram in more detail you will see that the trackage on the east (left) and south (top) walls has been completely revised. I felt that a scene of the BNSF crossing the main river was a must, but I couldn't figure out how to make it work. My first approach was to somehow try to fit the river in the upper left corner, on the grounds that this would leave more space for the other railroad scenes. Eventually I dismissed that approach, both because the resulting river was too narrow to represent the major, navigable, river that the city history required, and also because the 36" minimum radius meant that the bridge track would have to be at least partially curved, something that would have been avoided in real life.

So, I decided to try locating the river along the left wall. This meant sacrificing some potential industry there, but the resulting track was simpler and cleaner and thus aesthetically more appealing, at least to me. Moreover, the idea that the river would be at least 6' wide (960' in scale) meant that the bridge could be a signature scene on the layout -- if done well it would be something that people noticed first and admired. Then, I considered that immediately above the bridge scene, on the upper deck, was going to be the most active part of the freight yard. One tenet of two-deck design is that you want to balance the areas of intense operator activities, such as freight yards, so that no two such areas are located directly above/below each other. Thus, a river bridge would be an excellent counter-balance to the freight yard above.

All in all I was -- and am -- very happy with the river and bridge concept. For the south wall I decided to include a short (5') commuter station, and the downtown intermodal yard. Again, I'm happy with the location of these items, although the final trackage would be significantly changed from what is shown in the above diagram.

The final note from this March 3 iteration was a comment I wrote to myself about whether to transpose the identity of the main lines. I was concerned that this ostensibly BNSF-focused layout had the BNSF on only one deck. As it turned out, this concern would soon be answered in a different fashion.

My next step would be to address the freight yard design, which is a big enough topic to justify its own post.

Evolution of the iNdoor design, part 1

Previously I talked about the high-level design and the decision to use CAD for the detailed design. After I'd been using the CAD tool for a while I began archiving the design files with the date in the file name for posterity. I'm glad I did this, as these old files help me understand how the design evolved.

Here is a picture of the lower deck design on February 27, 2006, the earliest file save I have a record of:


Grid lines are 1' apart. This is comparable to the high-level design sketch from that earlier post.
At this point in the design process I was still getting used to the CAD tool. I hadn't started using text labels, colors, or providing any details except the outlines of the benchwork and the main track. I also hadn't done much work on staging yet.

Most of the track design at this point was nothing like the final design, but one area that was very close to final was the Union Station on the north wall:


I put a lot of thought into how many tracks Union Station should have. My concept of commuter train operations wasn't as well formulated then as it is now, per the layout concept description I recently posted, but I did know I wanted enough tracks to support heavy traffic and make operations interesting. This was a highly subjective decision -- the sort of thing about which reasonable modelers can disagree. Eventually I decided that 6 tracks would be too few but 8 just enough to give a sense of a busy Union Station.

The next challenge was fitting everything in. Each station platform had to be 10' long, per the maximum passenger train length. Granted, the maximum length for the commuter trains is only 5', but as this Union Station has a long history I couldn't seen any rationale for shortening the platforms from what would have been built in years past. (Reducing the number of tracks from years past does make sense in order to reuse the land, but reducing existing platform length would have had little benefit as the tracks would still be there.) When you then add the need for switch ladders on both sides, plus 36" minimum radius curves at each room corner, PLUS the need to have room for double track main adjacent to the station tracks, it was a struggle to fit it all in.

Fortunately, one question I'd toyed with during the concept phase was whether to have the station be stub (tracks that terminated in the station) or through (tracks that extend in both directions from the station). At that time I studied existing and past Union Stations, and noted that Kansas City had a mix of stub and through tracks, and thought that might be a neat idea. It was important to note that for the modern St Albans Union Station 3/4 of the traffic would depart in one direction -- towards the junction -- so it made sense to me that half of the 8 tracks would be stub ended, servicing only that direction. This would also make operations planning more interesting, as it introduces a new constraint regarding track assignments. Finally, from the design perspective, this meant that the switch ladder on the east side (left in the above diagram) would be significantly shorter, thus giving me enough space to fit everything in.

I've mentioned before that I love the intracate trackwork leading to congested city Union Stations -- not just Chicago but other cities as well. On the east (left) side I used curved switches to save space. On the west (right) side 3 double slips were used to help create a double crossover as the main entrance to the station. This is but a tiny fraction of what is used in Chicago, but it does give the feeling of complicated, congested trackwork that I was seeking.

This next picture focuses on the northwest corner of the lower deck (the lower right of the diagram). Although all of these tracks were redrawn at some point the basic schematic still remains in the implementation today:


The main junction between the two double-tracked lines is shown at the top. One main line is shown going diagonally from the lower left towards upper right (this is the N-S main). The other (the E-W main) may be difficult to identify because there are so many tracks in the picture. The three tracks to the far right in the picture, the ones going straight along the right wall, are the interchange tracks between the two main lines. If you follow these downward you'll see they merge into one, using curved switches in the bottom right corner, and that one track then connects them to the double main line. Although these tracks appear to be right next to the main line tracks, what the diagram doesn't show is that there is a widening elevation difference as the main line gains elevation and the interchange tracks slope downwards.

The elevation difference was because I decided early in the design process that the junction would be a bridge of one line over another, not a level crossing. This was another one of those decisions that required a lot of thought. A level crossing is certainly more interesting operationally. However, given the traffic density for these lines it seems to me that a bridge crossing would have been a requirement -- especially a century earlier when the Union Station would have hosted 40+ tracks and automatic traffic control wasn't even a concept. On the plus side, this gave me a good reason for introducing gentle grades (1% maximum) to add visual variety.

At the same time, I wanted the scene to contain evidence of there having been even MORE traffic in past years. Although both main lines are now double-tracked, the layout will have signs that more tracks were used on the main lines in years past. One example of this is the track which goes from Union Station to the E-W line. You'll see that it connects with the main, but also that two other tracks extend along the main line towards the junction. The purpose of this track is to go from Union Station to the commuter train storage and maintenance yard (on the layout peninsula). There is a dual track for a short distance which serves as a runaround track. These dual tracks are positioned as if they are on the same roadbeds that in years past hosted the 3rd and 4th track of the E-W main line -- back when traffic density justified that many main line tracks.

Perhaps the most interesting item in this diagram is that trains leaving Union Station on this side of the layout have 3 choices of direction -- one toward the E-W main line, and two toward either direction of the N-S main line. The radius for these tracks is tighter than the main line -- one of them actually is set at the 24" minimum radius for slow speed yards. All in all they succeed in providing the sense of an interesting, complex, network of track at the entrance to the Union Station.

There were a number of things that needed adjustment in this diagram, and these would be taken care of in later iterations. The biggest issue was the "S-curves". The back-to-back switches are just not realistic. There needs to be at least one car length between switches to avoid the S-curve problem.

Otherwise, referring back to the first diagram at the beginning of this post, the rest of the track shown for the lower deck would not survive future revisions. On the left side of the diagram you'll see a single track spur from the mainline. The idea here was that this spur would meander through city streets then ultimately end up on a landing along the river, going under the main line, and that the bridge over the river would be in the upper left corner. As I reworked this later I would toss out the idea of having remaining industry along the river as being both inconsistent with my vision for the city, and also a sign of trying to do too much in the space. This last point is purely subjective, but it was the conclusion I came to.

The last point I'll make regarding the lower deck is my decision to include a commuter train yard on the peninsula. Although the track for this yard would be revised, I kept the yard in that location. The question about whether a downtown yard made sense was another one of those subjective decisions. One option would have been to argue that there would be commuter train yards at the suburban ends of each line, where real estate is cheaper and where most trains would originate. This would also allow me to put some sort of interesting industry on the lower deck peninsula instead of a commuter yard. However, I eventually decided that consolidating all maintenance operations in one central location would be a money saver, and thus a likely result of the 1970s consolidation of all commuter railroads in the city, and that the real estate in question would have been available from other railroad uses that the SAMR (St Albans Municipal Railway) would have owned. In addition, the commuter yard operations are turning out to be at least as interesting as those of a freight industry, and have the benefit of being unusual for a model railroad.

So that's where the lower deck design was on February 27, 2006. At that time I'd also done some work on the upper deck, but it was not as far along:


This does roughly follow the high-level design concept for the upper level. The peninsula is used for a branch line, terminating in the railroad museum. The railroad museum concept would later evolve so that it now matches what is described in the high-level design post. There is a commuter station on the right side of this diagram -- that would remain in that location, but only after extensive modification.

There is a first attempt at a freight yard on the left wall, with part of the yard spilling over to the bottom wall. This attempt was entirely unsatisfactory and resulted in a long study of frieght yard design which I'll cover in a separate post.

As a final note in this post, you'll see there is no evidence of staging in either of these diagrams. In fact, there were staging tracks in this version of the design, but they were in separate CAD layers so are not shown. At this point they were very rudimentary. Much of the work over the next several months would be struggling to find a suitable staging approach. This will be part of the discussion in the next design post.

Egad, what a CAD

This post is about Computer-Aided Design (CAD) tools for model layout planning. The title actually comes from an obscure, one-act melodrama that is occasionally put on by high schools, more commonly back in, oh, say, the 1970s. Don't ask me how I know that.

I managed to avoid CAD for layout design for a long time. I downloaded a few demo products back in 2003 but after realizing they all had steep learning curves I stuck to graph paper, pencil, erasers, a ruler and a compass.

However, after I completed the high-level layout design and made my first attempt at a detailed staging design I realized that I was going to need CAD to complete this layout. I'd been working at it for about 2 hours when I realized that the approach I was taking simply could not work, and that I'd need to shift the entire track arrangement around. Then it occurred to me that this was likely going to happen many, many times given the nature of what I was trying to fit into the space. A tool that would allow me to shift whole track groups quickly from place-to-place, trying to find the best arrangement, was going to be essential if I was to complete the design in the same decade.

There are several CAD tools available for model railroaders. I'm sure I don't have a comprehensive list but CADrail and 3rd PlanIt seem to be the most popular choices. There is also a free tool from Atlas which apparently is acceptable if you are using their sectional track, and I've heard there is a model railroad version of Xtra CAD somewhere, but it didn't turn up in my quick Google search.

Which is the best? Heck if I know. Like almost everyone else I just picked one, learned it, and since it works I haven't bothered to try another since the learning curve is steep for each tool. I've read a few reviews of the various tools in Model Railroader, but they are careful to avoid making any one tool look better than the others.

So, I picked 3rd PlanIt only because when I tried the demo I was able to locate quickly the templates for the N scale switches I was going to use. Not the most scientific approach, but at least I knew it was going to work for me. I've found it a good tool, but if I had to recommend one now I'd suggest you look at CADrail only because I can't get the 3rd PlanIt people to respond to my emails.

The learning curve is steep even if you are adept at computer use and even have CAD experience, say from home design software. Actually I can't imagine how someone who has limited computer experience could possibly learn this tool on his/her own. Yes, part of the learning has to do with getting used to the concept of working with objects segregated by layers -- only some of which may be visible at a given time -- and part of it has to do with getting used to thinking in three dimensions. But most of the learning has to do with getting used to setting up the track and the connections between the track, including topics like easements, parallel track, and connecting track that doesn't align to the nanometer.

In my case I spent maybe 3 weeks getting the lower deck designed, then did the upper deck over the next 2 weeks, then re-did the lower deck now that I really understood the tool.

And once you are skilled at using the tool you'll find, if you compare notes with another skilled user, that your approach and his/hers are completely different, yet both are effective. This is because the tool has so many options that it's likely no two people use it in exactly the same way.

So, thus far all I've said is that I used 3rd PlanIt to design my layout, I am skilled with the tool, and it took me a long time to learn how to use it. But the real questions are: do I consider it worth the effort, and if so what are the advantages? The answer to the first question is an emphatic yes -- I wished I learned it years ago and saved the time I spent doing smaller layout designs on graph paper. The answer to the second question is that these are, IMHO, the advantages of using a CAD tool:

1. Speed. Once you are adept you can put down the initial version of a track section at least as fast as you can using graph paper. After that is done subsequent adjustments can be done in mere seconds or minutes. You can save literally hours or days with a single redesign effort.
2. Precision of design. On paper, no matter how hard you try to be exact, you can too easily "fudge" the angle of a switch or the radius of a curve, and deceive yourself about the workability of a track arrangement. With CAD what you design is what you get. "Fudging" is only possible if you cheat by, say, forcing two tracks together that don't really fit. If you use the standard connect tools that won't happen.
3. Precision of implementation. CAD allows you to know the exact location, down to 1/32nd of an inch if you like, for a given switch or start of a curve.
4. 3D and overlays. It is a challenge to figure out how elements fit together in a three dimensional space using graph paper. With CAD you can easily select which layers to view, allowing you to see how different elements fit together without distractions from other elements. Futhermore, most CAD programs have 3D views so you can confirm it all works.
5. Precise calculations. Will that siding be long enough? What is the exact slope of this grade? What is the exact radius of this curve? All these and more are quickly answered with CAD, but often can be calculated only approximately, and after a lot of work, with graph paper.
6. Easy printing and sharing of designs. A nice side effect of CAD.

In addition, there are other features of CAD which I haven't used, such as testing out scenic views or actual train operations, which many people find helpful.

The only caution I'd give to someone using CAD is that it really helps if you have experience building from CAD before you decide that your CAD design is "final". This is because CAD's extremely precise calculations can mislead you about how the design will translate to reality. My plans, for example, are calculated to the 16th of an inch. When you start working in your layout room you'll find that real life isn't always like that. Floors aren't always level and walls aren't always plumb (in fact, they usually aren't). The peninsulas you build may not be exactly perpendicular from the wall. You may also find that if you carefully plot two locations of a line from the CAD to your benchwork, that when you extend the line outwards it doesn't seem to correctly line up. In part this is because 1/16th of an inch is really small -- your pen mark may be that wide! You probably will need to check measurements again and again at different locations, and also be prepared to adapt your CAD design slightly based on what you encounter on the benchwork. Once you've done this once or twice you'll take it into account when doing your next CAD design, and leave yourself a little slack room in the design.

So, I used CAD for the iNdoor layout design, and then later for the Garden railroad as well. In future posts I'll describe those designs.

Design influences: 2003-2005

This is my final posting under the “design influences” theme. I have covered pretty much my life story from a railroad perspective, starting at age 9 months and ending just before the design of my iNdoor layout began in November 2005. Probably I wrote too much, but what the heck, it’s my blog, and in the process I’ve gained some insight into why I designed the iNdoor layout the way I did.

The years 2003-2005 were frustrating for me from a model railroad perspective. I very much had the itch to build, as I was inspired by my new discovery of N scale, but I had minimal space and we knew we were going to move out of California “real soon now”. As a result I put some effort into designing 3 layouts during that time, each intended to be portable to allow for moving them later. None were built, but each of them taught me something that I used in the layout I’m building today.

The first layout design was done in early 2003 with an “Espee” (Southern Pacific) theme covering the line from Klamath Falls to Eugene, Oregon in 1944. I'd been reading from various of the model railroad "Elders" about how Real Model Railroaders(tm) built pure prototype layouts, so I kinda felt I needed to do the same. I was looking for a prototype that would support realistic model railroad curves and was attracted to the Espee because it had been, until recent acquisition, the dominant railroad in the part of California where we lived. The line from Redding to Mt Shasta is great for model railroads, but it has already been modeled by many people and clubs. The Eugene-Klamath Falls line offers tons of tight curves, including at least two horseshoes, plenty of tunnels, and one really cool train town (Oakridge). Since the steam era ended the line has become pretty bland, but in 1944 the town of Oakridge was a hotbed of action, full of cab-forward locomotives. Here's a shot of Oakridge yarda few years later, when it was still interesting.

I went to topozone and downloaded images of topographical maps of the area, and printed and taped them together into a scroll of the line. Then did some research on the line itself and went to work trying to put it into a layout. In the end I gave up the project, although I still have the drafts. The main problem was trying to build a layout with a long, steep climb on a portable platform. I actually tried designing a portable mushroom layout (if you don’t know what a “mushroom” layout out is, just understand that this is extremely difficult to design and build in a fixed location, and probably almost impossible as a portable layout).

I also had certain other nagging doubts about that layout approach. Did I really want to limit myself to a single railroad modeled in a single year? Did I really want a layout that, while a pure prototype, was limited in terms of operational variety? And did I really want to deal with yet another mountain layout with steeply-sloped track? As it turned out the answer to all these questions was “no”.

My next layout inspiration arrived with the October 2003 Model Railroader, which included a feature on Hutchinson, Kansas, including a sample N scale layout. It was so interesting that I went out and bought that month’s copy of the sister publication, Trains, which had more details on Hutchinson.

There is nothing special about that town, and looking back on it now the layout doesn't seem so interesting either. But at the time what made the layout so attractive to me was that it featured two major through lines – the BNSF and the UP, both with lots of trackage -- plus a regional and a branch line, all in a compact city space. The layout featured lots of junctions and operational possibilities, plus the ability to run through trains at full speed. Although it included a one loop helix it could be easily have been modified to use level track exclusively.

I pulled out graph paper, a ruler, and a compass and went to work. I quickly realized that the designer had assumed sharp N scale curves and short consists. No matter, I thought, I’ll expand the space. Realizing I’d need to make the layout portable I assumed a set of 4x8 tables in various configurations, and tried minimum radius standards of 48” then 44”. I had one possible solution that required lots of hand-laid, curved switches, which I was excited about until I bought some rails and ties and found out how hard it is to actually build such a switch. Once I realized the challenge involved I redid the design using Peco code 55 switch templates.

In the end I didn’t build it as I realized it would take a long time and all of my garage space just to assemble just the benchwork and trackwork. However, I did love the idea of a Midwestern city layout with junctions between main lines, industrial districts, and without major slopes. After that time I did not consider any other theme for the iNdoor layout.

So, things kind of idled until the March 2005 issue of Model Railroader, which included a review of Kato’s 1950s era N scale California Zephyr. I suppose it’s the same for all of us – there are certain prototypes that we think are just the coolest thing on the planet, and for me this was one of them. Maybe it was watching the Zephyr fly by the tracks in LaGrange, Illinois during its last, pre-Amtrak months when I was just an 8 year old boy. For whatever reason that version of the Zephyr has always been my favorite passenger train – ahead of even the similar-looking Super Chief and the 1930s era Pioneer Zephyr. I *had* to have it.

So I looked up N scale shops on the web and located Wig-Wag, who has been my primary N scale dealer ever since. I got the train and loved it. Now I needed a place to run it.

At this point the need for a layout NOW was suddenly bumped to the top of my priority list, so I was more willing to sacrifice most of my other layout desires. I designed a 4x12 -- the minimum I figured I could get by with since the Zephyr was nearly 9' long with engines. It was a congested city layout, with dual track in a folded figure 8 (that is, it looked like a 4 track oval but at one side there was a crossover) with 1% grades, one through station, and industrial tracks in the center. I actually ordered some code 55 track, extended the 4x8 in the garage to 4x12, and started the process. Then we very suddenly decided to move immediately and the project was permanently scrapped.

A couple months later we moved to a corporate apartment in Kansas and built a temporary 2x16 layout just for play and to learn about new building materials and DCC:


Only a few months after that photo we were moving into our house in Colorado and I was finally planning my permanent layout.

So what did I learn from this time period that influenced my current model railroad design?

1. Learn to ignore the Real Model Railroaders(tm). Most model railroaders are accepting of pretty much any way to do model railroading. The cliche is: the only rule of model railroading is that you are doing it right if you are having fun. This is especially true of the garden railroading community. Alas, as with most human activities, there is a subset of the group who think that their way is the only "real" way. You are a much happier model railroader once you have the confidence to do it the way you want, not the way the "Elders" think you should do it.


2. A city makes for fun model railroading. In the prototype, I love lots of complicated, congested trackwork. The operations are interesting, the track itself is interesting, and the whole question of how the engineers figured out how to make it all work in that tight space is interesting (and very similar to the challenge we have when we design our model railroads). Throw in the fact that cities are usually places where many railroads -- sometimes literally dozens -- interact and interchange and the modeling options are almost endless. I decided that the best layout design for me would be to focus on a mainline going through a congested city.


3. Simplicity should balance ambition. The first two designs described above were trying for way too much. The third design featured all kinds of compromises in the interests of having something that could be built and running in a shorter timeframe. Of course, the third design wouldn't have been that satisfying by itself, but this was due primarily to space limitations not to the design approach itself. I realized I was going to need to contain my wildest dreams if I was going to come up with a feasible layout design, which meant that things like hard-to-build custom structures and track should be avoided.


4. Subtle grades are a positive. My first layout was absolutely flat, and that didn't look quite right. My next several layouts had grades from 2% to 5%. While these are prototypical in some situations they are also unusual and require special operational considerations. Trying for grades less than 1% is a design challenge, but there are aesthetic rewards. The gradual changes add a clear, if subtle, sense of realism while at the same time not adding operational challenges. I'm not saying steep grades are bad ... I'm just saying I hadn't realized that gradual grades could be cool too.

So that takes us to November 2005, when we signed the contract on our current house and I started actually designing the layout itself. That will be the topic of the next design post.

More about Curves

As an addendum to my post on curves and radii, I took a few pictures of the Kato Zephyr around various curves to demonstrate how the degree of curve affects appearance. Apologies that the lighting/composition is poor, but hopefully they still illustrate the concept. Here is the Zephyr circling the 18" staging loop (about 24˚):


In particular, look to the left of the photo where you see two cars connected at a sharp angle. That just doesn't happen in the prototype.

Here is the Zephyr around a gentler mainline curve of 41" radius (about 10.5˚, still very sharp by prototype standards):


Here is the Zephyr around a short mainline curve of 51" radius (about 8.4˚, still sharp by prototype standards, but now within the domain of a realistic curve):

A Degree in Curves

What has to be out of scale in even the most spacious layouts? The
curves! – John Armstrong, The Classic Layout Designs of John Armstrong, p. 74.

On my post on my 4th, experimental layout I mentioned that I ran into an issue with curve radii. In this post I’ll describe the results of the subsequent research I undertook on curves.

First, of all there are two types of limitations for model railroad curve radii: operational and aesthetic. Our model trains are designed to be able to negotiate much, much tighter curves than prototype trains, so there has been a lot of published work addressing operational limitations. I’ll cite some of that work here, but my main concern is the aesthetic side.

Operational radii limitations

In his terrific book, Track Planning for Realistic Operation, John Armstrong discusses radii limits on pages 73-77 and provides this table:


Armstrong goes on to define each type of curve by the type of equipment you can reliably run on it. (A much more detailed table is provided by the NMRA, standard RP-11, for those trying to find the absolute minimum curves for their situation.)

In his book John Armstrong also provided a great suggestion for pushing these operational limits, demonstrating that the main issue with tight radii occurs when transitioning from tangent (straight) track to curved track. That is the point where the curve places the most strain on couplers and axles and is most likely to cause derailments or decoupling. Armstrong called that the “coefficient of lurch”, and showed how spiral easements – a section of track that transitions from curve to tangent – can reduce the coefficient of lurch and allow a tighter radius than would otherwise be possible. On page 75 he shows an example where an 18” radius HO curve with spiral easement creates less stress on the train than a 24” radius curve without the easement.

I highly recommend this section of Armstrong’s book for anyone who is trying to squeeze tight, but operationally sound, curves into a layout. Actually, I highly recommend the whole book for anyone interested in getting serious about layout design.

Aesthetic radii limitations

When you are building layouts with curves that test the limits of how tight curves can go you don’t worry about the aesthetics of how trains look going around the curves. I mean, it’s pretty obvious that an HO train going around a 15” curve or an N scale train around a 9” curve don’t look anything like the prototype, with the trucks turned at extreme angles and the ends of the cars hanging far over the sides of the track. You know it looks wrong, but due to space limitations that’s just something you deal with. That’s the situation I was in with my first 3 HO layouts.

At some point you may decide that for your NEXT layout things will be different. That’s how I was with my 4th layout, my first N scale experiment. I was still dealing with a 4x8 space, but now in N scale. A 17” radius curve in HO scale is very sharp, per the Armstrong table above, but in N scale it’s a broad curve. So I built a bunch of 17” curves, and even built one curve to 20” radius just to see how a “very broad radius” curve looked. But as I watched the trains go around it something slowly dawned on me. Yes, the trains did not look as ridiculously toy-like as they did on very sharp curves, but even the 20” curve was still obviously way too tight.

Fortunately, John Armstrong also wrote a lot about the aesthetics of railroad curves (the quote at the start of this post was how he began one article) and that gave me some good information to start my research. First, the conventional measure of how sharp a curve is, at least in the U.S., is degrees of curve, which is how far a curve would go around a circle in a 100 foot arc. For example, suppose you had a circle with a 400 foot circumference. Then 100 feet of arc would cover 1/4th of the circle, or 90˚ (since a full circle is comprised of 360˚).

Prototype railroads naturally try very hard to limit curves – both the frequency of them and the sharpness – because curves add drag to the locomotive pulling a train much the same way that upward slopes do. Many mainlines get by with curves no sharper than 2˚ and in flat country a 5˚ curve may be unusual. The famed horseshoe curve on the Pennsylvania Railroad came in at 9.25˚, which Armstrong saw as the standard for comparing mainline curve sharpness. Finding curves sharper than that on standard gauge mainlines is hard – up to 12˚ can be found in a few areas with difficult topology and/or congested urban areas, and anything above that is rare. Narrow gauge commonly went much tighter – the Rio Grande lines typically had 24˚ as their maximum curve sharpness, and one famous narrow gauge curve in Utah was an incredible 60˚. But narrow gauge trains also typically ran at very slow speeds with very short cars

So how does this compare to our model empires? Well, a 5˚ curve in HO requires an astounding 158” radius—that’s over 13 feet. 10˚ is a little better at 79”, but that’s still over 6.5’ – and if you tried a U-shaped curve with that you’d need a diameter of over 13’. N scale is much better, but 10˚ is still about 43” radius – over 3.5’.

To better understand how model railroad radii compare to the prototype you can construct a simple spreadsheet table. Here is a small sample of a table I created in Excel:


In order to create this yourself, put the radii in the left column (A), then put the following formulae in columns B and C:

=((1200/160)*180)/(3.1416*A[row#])
=((1200/87)*180)/(3.1416*A[row#])

To explain each element in the formula:

1. “1200” is the number of inches in 100 feet. 100 feet is the length of the arc that we use as the basis for the degree measurement. When measuring for large scale you’ll want to use feet as the measurement, so change this to 100.


2. 160” or “87” is the scale you are using, in this case N and HO respectively. Substitute 48 for O scale, 220 for Z, etc.


3. 180 is the number of degrees in a semi-circle. You might think we’d use 360 for a full circle, but because we are basing this formula on radius, which is half a diameter, we cut the number of degrees in half as well.


4. 3.1416 is an approximation for π.


5. The “A[row#]” is the number of inches in the radius. When measuring for large scale change this quantity to feet – and do the same for (1) above.

It helps to create such a table yourself because it gives you a chance to play with the numbers and see the possibilities for your situation. But no matter how you slice the numbers you’ll see why John Armstrong made the statement which started this post – with curve radii the difference between the model and the prototype is just huge.

Out of doors the situation isn’t quite so bad, although it is still challenging. With large scale minimum radii are measured in feet, not inches. If you model the narrow gauge Rio Grande, as I am doing, the 24˚ minimum translates to a bit under 12’ radius in 1:20.3 F scale, which means a half-circle turnaround requires a diameter of about 23.5’. That’s still a lot of space, but doable on many outdoor lots.

For indoor layouts John Armstrong recommended that model railroaders set a minimum radius based primarily on operational requirements, but that they made sure to include one curve of realistic gentleness – 10˚ or less – for aesthetics. This is a good recommendation, but there are also other things you can do with regard to curve radii, and I cover those in the next section.

Dealing with unrealistically tight curves

Here is a short catalog of things people have done, or can do, in response to the realization that model railroad curves look unrealistically tight. These are not independent solutions, as it is possible to use a combination of any or all of these solutions on a given layout for different situations.

1. Ignore the problem
   
   Seriously, if it doesn’t bother you don’t worry about it. We have to make a lot of other compromises in our make-believe empires. Alas, for me this doesn’t work … for me many a picture of an otherwise terrific model railroad has had the illusion spoiled by an curve that is obviously too sharp. This depends entirely on your personal preference.



2. Hide the problem
   
   This is probably the most common solution, other than #1. Put the curve under a tunnel or behind a viewblock. I did this with my second and third layouts (well, that is I would have if I’d completed the scenery) and if done well it can also hide the overly short consists we tend to run on our smaller layouts.
   
   However, this is not perfect. Except for switches, curves are where most derailments occur, so you have to arrange some kind of access to those tracks. Depending on your chosen model theme the viewblocks and tunnels may seem out-of-place (the original Rio Grande was positively allergic to tunnels, for example), so you may be introducing an element that doesn’t look appropriate for the scene. And finally, for smaller layouts, like my third one, hiding all the curve track ends up hiding the majority of track, which may not be as pleasing as you thought it would be when you started.



3. Disguise the problem
   
   This is different than hiding the problem in that you leave the curves out in the open but control the optical viewing angles to make the curve sharpness less obvious.
   
   The most common way to do this is to move the layout to eye level or near eye level, and the second most common is to arrange the track so that viewers can see the train only from the inside of the curve, not the outside. When used together this makes it almost impossible to assess just how sharp the curve is.
   
   The eye level trick, by itself, certainly helps because the viewer can’t look down on an empty track and see how obviously sharp it is. In fact, this also helps disguise unrealistic “spaghetti track” formations because the viewer only sees the side of the nearest track. However, eye level doesn’t help quite so much when the viewer is on the outside of a tight curve, as the angle between cars tends to be a visual giveaway.
   
   Also, eye level layouts are the subject of one of the hobby’s great debates. Proponents love them because “you see trains just as you do in real life”. Critics (and I am one) argue that in “real life” we often seek out platforms from which we can look down on trains and get a better view, so a view from above is actually a good thing. Furthermore, we argue, if you want the eye level view you can still get it with a lower layout by bending or sitting down. Lastly, not everyone has the same eye level, and shorter people and children tend to get short changed with layouts set at 66” or so above the floor. I’ve noticed in recent years a trend away from the eye-level traveling layouts that were prevalent 10 or so years ago.
   
   The view-from-inside-the-curve trick is useful anytime, even from higher levels, although it’s most effective at eye-level. Unfortunately you can’t always limit your layout to only inside-the-curve views – and in many cases you can only build outside-the-curve views, such as with a rectangular-shaped show layout. However, if you have an inside-the-curve view you can take advantage of that to use a smaller aesthetic radius than you use elsewhere.



4. Build layouts that require minimal curves
   
   Tight curves are only a problem if you need curves. A long industrial, point-to-point shelf layout doesn’t need them, for example, except for very short lengths. Or if your layout requires only one or two U-turn curves you can hide those (per point 2 above) and emphasize the rest, including building straight track over the hidden curves.



5. Choose curvy prototypes
   
   Kind of the opposite of (4). Instead of choosing a layout theme that requires no curves, choose a prototype that had lots of very tight curves that you can either match exactly, or perhaps model just a little bit tighter.
   
   Two very obvious examples of this are narrow gauge railroads, which as mentioned above commonly had curves of 24˚ or tighter, and trolley systems, which were made to negotiate curves around street corners. Also popular for modelers are the common industrial short lines of the last century, run by very short steam, diesel or even electrical locomotives, that moved shortish (50’ in length or less) cars amidst very congested commercial districts.
   
   These types of prototypes are popular for many reasons, but certainly one key reason is that they fit into our layout rooms without having to compromise the curves.
   
   The only problem with this solution – as with solution (4) – is that it only applies to certain layout themes. If you want a layout featuring heavy mainline traffic these solutions don’t apply.



6. Convert to a smaller scale
   
   Admittedly this is not a viable option in most situations, since most people have a strong reason for choosing a given scale and often already have a sizable stock of items in that scale. But this can be a really useful design trick when viable. Alternatively, you can use this same trick by forcing yourself to design a layout for your space in a larger scale, then switch to your own scale.
   
   You see, most people try to cram as much layout as they can into a given space (count me as one of those guilty of that sin). Double the space available and few of us will simply expand the same basic concept to the new space, but instead most of us will try to add more towns, yards, and industries. But what if you struggled through a given layout design for a limited space, making the normal sorts of compromises before finally getting a design that you think you could live with, and suddenly someone offered you 3.5 times the space – or even 7 times the space? What if instead of trying to cram more into that space, you decided to keep your previous design but simply apply it to the larger space, using longer trains, more space between towns, and larger radii?
   
   To see what this might look like, consider John Armstrong’s famous personal layout, the Canandaigua Southern. He chose O scale, which was still very common in the 1940s when he started the layout. Here is a map of that layout taken from the March 1971 Model Railroader:
   
   
   John spent a lot of time designing this, a process he described in an article which can be found today starting on page 46 of The Classic Layout Designs of John Armstrong book mentioned earlier. Like all of us, he had to make compromises to fit everything in. He settled on a minimum radius of 48”, which is about 30˚ in O scale, and of course accepted shorter consists and a smaller yard than he probably would have liked. The fact that all track was handlaid meant it still took him decades to complete the line, with only partial scenery, but nevertheless the layout gave over 50 years of enjoyment to Armstrong and the large number of his friends who helped him build and operate it.
   
   Now imagine you had exactly the same room, with exactly the same layout, with curves and towns at exactly the same location, but this time you worked in N scale. That 48” minimum radius now gets you curves of slightly under 9˚! You can triple – or more – the number of tracks in the yard and the length of your trains. Or, if you don’t want to add that much length to your trains, you can increase the apparent distance between towns.
   
   Consider that Armstrong’s personal layout is universally considered a great success. Not just because it was so innovative (which it was – no other layout has pioneered so many influential design concepts as this one did) but because it was FUN for all involved. An N scale layout, in the same space with the same essential design, would generate just as much fun, but the trains would look much more realistic.
   
   So, apply that example to another layout. Let’s suppose you’ve designed an HO layout for your available space but you’ve got some nagging concerns. Now try doing the exact same layout in exactly the same space, but in N scale. Wow. You’ll have the same schematic but with a lot more room. Or, suppose you can’t change scale. Instead force yourself to design a layout for a space of about ½ of what you actually have, then after you polish it, convert to the space you actually have.



7. Set very high minimum radii during the design phase
   
   So, you’ve tried everything else, but you still don’t have a solution that works for you. You care about getting realistic curves (otherwise #1 would work for you) but for various reasons none of the suggestions given above work: you can’t hide/disguise the curves, the prototype you want won’t permit you to use tight curves realistically, you can’t move to a smaller scale, and the trick of pretending to have a smaller space than you really do doesn’t work for you.
   
   If this is your situation, then you are where I was in 2003 and 2004. So I tried something else. Most layout design books will recommend that as an early design step you set some standards, such as “minimum switch size”, “track spacing”, “maximum train length”, and of course “minimum radius”. These standards may vary depending on situation – such as separate standards for mainline, branches, yards, and staging— but within a given category they are the basis for your design.
   
   So, set your “minimum radius” standard to a very high number and see what kind of layout you can design. For me I chose 48” as an N scale minimum and started trying to design layouts using that as a rule. It was enlightening in a way that can only be understood when you actually try to do it – as opposed to reading about it. Consider, for example, an around-the-walls kind of layout. A 48” minimum can easily be used in curves in the corners, but this means that the tangent track between two corners will be a full 4’ shorter than if you use a 24” minimum curve and 5’ shorter than using an 18” minimum. Let’s suppose you have a 12’x12’ room and that you generally keep track at least 6” from the walls. This means that if you use an 18” minimum radius the longest tangent track you can have between two corners is 10’ but that for a 48” minimum radius the longest tangent track is only half of that.
   
   That example describes only one of the early discoveries you’ll have. As you work more with the layout design you’ll discover ways to work with the larger radius curves, such as working switches into the 48” curves. Since 48” is a very gentle radius in model railroading terms transitions from curves to switches flow better, especially with spiral easements. And if you use a switch like the Peco code 55 “long”, which uses a 36” constant radius on the diverging route, or the Peco code 55 curved switch, which has 36” for the outside curve, the flow is even better.
   
   Eventually you may find that your ultra-wide radius is workable AND that the resulting track will flow much more easily. Of course, there will be sacrifices in terms of what you can include – there have to be – and only you can determine if the trade-off is worth it.

My personal solution

That concludes my discussion of options for modeling realistic curves. So what did I end up doing for my layouts?

For the iNdoor layout, after working with 48” for a while I tried 44” and 36” to see the difference in terms of layout planning. I then set up a number of curves with temporary track to view the appearance of trains on the various radii. What I discovered wasn’t surprising. While a difference of 5” makes a huge different in appearance for trains on small radii, such as going from 10” to 15” – it makes only an almost imperceptible difference in appearance in large radii, such as going from 43” to 48”. Once I recognized this I really had to question whether the benefit of going the extra effort for 40+” radii was worth the cost in terms of design trade-offs.

Eventually I settled on 36” as the absolute minimum for the mainline, with the understanding that I’d go above this as much as possible with each curve. This is about 12˚, which is still very good for a model railroad, and in a congested city setting is reasonable. Plus the fact that most curves are wider than that, with probably half at 40” or more, helps the appearance even more.

One other point is that in the prototype there are tight curves in special situations, such as congested yards and industries, and in those cases very slow speeds (10 mph) are required. One of my favorites is the curve leading from the Burlington race track line to Chicago’s Union station that I rode on as a youngster. I remember vividly how the coach trucks would squeal loudly going around that curve. For those situations I set a 24” minimum radius (18˚) and use it only in the approach to Union Station and in two local switching areas. I hope to one day include a sound system that duplicates the squeals of the wheels around those curves.

As you read this keep in mind that my personal minimums are on the extreme end for this hobby. In years of reading about layouts in magazines I’ve never seen any other layout with minimums this high. (One N scale layout in an oval-shaped dining room employed a lot of 48” curves along the curved walls, but also used 12” curves at a wall with a right angle.) Usually featured HO layouts have smaller minimum radii than I have for my N scale layout.

I do have smaller minimums in the hidden track, such as staging, since aesthetics are of no value there. However, I still stick to an 18” minimum in staging to aide in smooth operations to assure that I’ll always be able to run any equipment that I might acquire. (Note that the NMRA standard mentioned above states that 21.5” may be required for steam locomotives with a rigid scale 28’ wheel base. However, that standard is now over 20 years old. I know of no mass-produced N scale equipment built in the last 20 years that can’t run on a radius of 17” or less, so any exceptions are likely to be expensive custom-made brass imports, which I don’t bother with due to cost and difficulty running under DCC.)

For the outdoor layout the situation is different. There will be no staging, no hiding and no disguising. For the outdoor layout, what you see is what you get. Fortunately as I noted earlier my prototype, the narrow gauge Rio Grande, had a standard of 24˚ curves on the mainline so I should be able to duplicate that with an 11.75’ radius minimum. If I have to compromise in one or two spots in the freight yard to an 11’ or even 10’ radius I’ll still be within 28˚, which is also realistic for Rio Grande narrow gauge slow-speed operations. The key factor is that I’ll be running prototype narrow gauge cars from the 1880s, which were very short and thus looked appropriate around curves such as those.

Design influences: 4th layout (my first N scale experiment)

I mentioned that in 2002 we revived the Märklin layout in the garage. This was definitely fun, especially for the kids, as the layout had plenty of track, locomotives, cars, switches, and an interesting main line. But at the same time I had some nagging doubts.

I'd transitioned from a non-active model railroader to a quasi-active armchair modeler in 2000. I'd started subscribing to Model Railroader, and later Garden Railways, and had attended the 2000 NMRA convention in San Jose with my older kids. As I learned more about the contemporary hobby I became interested again in American prototypes and in the finer details of modeling. The old Märklin layout, with it's European prototype and Märklin's tinplate heritage (such as the third rail and locomotive pickup shoe in the middle), wasn't quite what I'd been dreaming about. The other problem was that Märklin is very expensive relative to the competition, and especially so in the U.S.

So it came to pass that on my birthday weekend in 2002 my wife sent me and the kids off to buy $500 worth of Märklin stuff for the layout, which was enough for one locomotive and one freight car. I headed out towards Redwood City, where there was a European train shop and a restaurant with a playground, when suddenly I turned to the kids and said: "You know, for $500 we could build a whole new layout in N-scale, and anything we added to that would be much cheaper." The kids loved the idea (especially my son), so I turned the car around and headed for Santa Clara, home of The Train Shop, instead.

The inspiration to jump to N scale surprised me as much as anyone, but apparently the idea had been processing in my subconscious for a while. There were a number of factors that made this an easy decision:

1. The space advantages of N scale were obvious. I'd first thought of N scale when strugging with the Märklin layout design in 1990. Given the tiny space I had to work with in our California home, N scale seemed like a good choice.
2. I was ready to get out of Märklin, for the reasons stated above.
3. I had little sunk cost in HO, or really anything except Märklin. All my old HO stuff was either really cheap (from the first layout) and out of date, or intended for the early 1900s (second layout) and not what I was interested in modeling now. My son had a very small selection of modern Bachmann HO, but not enough to make me stick to HO as a cost savings.
4. Although N had not held my interest for most of my life, over the prior two years I been reading articles on N scale layouts and about N scale in general and saw a few really good ones. It now seemed viable to me.

At the Train Shop I was introduced to their N scale pro. I'd seen him before over the years, but never worked with him until then. He was extremely helpful. We started talking about track. He asked me about code 55 vs. 80 and I said 80 because I didn't want anything that might make operations more difficult (I regret this now, but then they didn't have Atlas code 55 then). He suggested Atlas flextrack with Peco switches, which is what his N trak club used, and I went with that. He introduced me to Tortoises, and helped me get various Atlas switch boxes and wires, and some cork roadbed. We talked about DCC, but the cost and hassle (they didn't have factory DCC then, and installs were often a challenge) made me opt for cab control He showed me a couple of power packs for that, then we looked at rolling stock.

My son loved the Kato Amtrack Superliner Phase III sets which had just come out, so we got two of those and two P42 engines. We also got an Atlas dash-8 BNSF locomotive (my son loved Santa Fe, I loved Burlington, so BNSF was the obvious compromise) and a variety of freight cars.

I got home, cleaned off my son's 4x8 table, and tried to figure out what to build. I decided it would be a quick-and-dirty, temporary layout with as long as possible a main line (now that I was in N scale I wanted long trains, not the very short trains I was forced into with HO scale), double track, with curves as broad as possible (again, now that I was out of HO scale I was looking forward to curves that were not ridiculously tight). Also there would be very few switches, as they didn't have many at the shop and I figured I could add them later. I would throw in easements and superelevation, two concepts I'd learned about from the magazines and had never tried before. Using scrap wood I got the whole thing complete in less than a week. It was a dogbone schematic, folded over three times into a figure 8 double track, switchbacking it's way up a mountain, and resulted in a main line loop of 120' in just a 4x8 space:


Honestly, it doesn't look like much, but if the goal of model railroading is to have fun (and it is), then this was a great success because we had fun for several months. Eventually we covered it up and moved it to this side to focus on other projects, and in 2004 I tore it down thinking I would start another layout. (That never happened, as plans for moving out of the state kicked in.) But the layout definitely served its purpose as a learning tool and for model railroading fun.

So what did I learn from this that influenced my designs today?

1. N scale is cool. The whole experience was neat. After this there has never been any question that my dream indoor layout was going to be N scale.
2. I like very long trains. You don't need a train to be a full scale mile long (33' in N scale) to look like the train is realistically long -- 12' to 16' is usually sufficient depending upon the viewing angle. This is why my current layout standardizes on 12' trains and supports 16' through trains.
3. This curves thing was more complicated than I realized. I'd always had to build HO layouts with curves classified "sharp" or "very sharp", and now I had a layout that had "broad" and "very broad" curves. But even on the 20" radius curve trains still didn't look realistic going around. This realization led to a full study of the curve problem, and I'll describe this in a future post. It's also why my current iNdoor layout has a 36" minimum radius on the main line.
4. I like modern trains. This was the first time I got into modern container cars, autoracks, etc., and I found them very cool. By contrast 1940s stock cars and reefers aren't so interesting to me. I didn't finalize on the modern era for a layout back in 2002, but by 2004 I had done so because of this.
5. Digital (DCC) control was a must have for my future layouts. I'd never tried cab control before. My first two layouts only supported one engine at a time and my third layout used Marklin digital control. I used cab control with two cabs and common rail wiring. This wasn't hard to set up, but it was more work than wiring for DCC. However, running trains with cab control involved a lot of manual overhead and was something that the kids had trouble mastering. In addition, I missed having the train lights stay on when the train stopped.
6. I like double track with trains passing and lots of traffic. So my current layout is double-tracked with heavy traffic.
7. Good track laying is a must. At first all my locomotives were four axle diesel. When I added a six axle diesel I had to rework many of the rail joints, and then again after I got a steam engine. It's worth it to practice and redo as needed until you get the technique right, and to plan the layout design to facilitate quality laying and maintenance of track.
8. The 2-3% grades were getting old. All my layouts, except the very first with my dad, used grades to gain elevation and to justify having a lot of track in a compact space. I'd begun to just assume that I'd always build mountain railways. However, on this layout more than one item of rolling stock broke because it rolled down hill and fell off the layout. In addition, putting trains on a sloping track can be a pain. So, I'd begun to think about city layouts with 1% or less grades, and that is where I ended up.

After this layout was torn down I spent some time designing possible N scale layouts ... each one helping me narrow down what I'd do for my ultimate dream layout. I'll cover that in a future post.

Design influences: through the eyes of a child

I mentioned before that my third layout was put into storage after I had to give up the space due to the arrival of our second child. Even before that I really stopped any work (or play) on that layout after our first child was born at the end of 1993. Between 1993 and 2002 I did no layout work (with two special exceptions, as noted below) because children just kept coming -- 4 in all -- the last one born in 2000. But just because I didn't have space or time for a layout didn't mean I didn't have time for trains -- only now my train interest was tied in with the children's. Call those my "Thomas the Tank Engine" years .... and although my kids are no longer Thomas fans, those years influenced how I designed the layouts I'm building today.

Kids and trains just seem to go together. Yes, Thomas is part of that, and I read those books to every one of our kids, and watched the videos and bought the toys. The kids also loved other train videos and lots of other train toys:


They also loved trips to train museums, and I was happy to oblige. We saw every train museum or attraction within a 4 hour drive of San Jose, California, with many trips especially to Sacramento. We rode many tourist trains -- from the very authentic to the built-for-tourists, like in Nevada City. We also had "Saturday trips with Dad" every week since early 1996, and once every month or two I'd make that a trip on the Caltrain "double decker train" -- usually to a stop where we could have ice cream and lunch then come back.

For the kids who were really interested (usually mostly my son) I'd make trips to the Santa Clara Depot model railroad and watch any activity in the freight yard. He'd get so excited to see any train go by -- as I used to be at his age.

For toys I focused initially on the wooden Brio/Thomas/copy trains. We still have a very large bin of them in the basement and get them out when we have younger visitors. Interestingly, when I build a layout for the visiting youngsters our oldsters will spend a lot of time playing with it as well. ;)

Later my son's interest in trains was so strong that he asked for, and got, a Bachmann HO set for Christmas. Here he is enjoying that gift at age 4:


He enjoyed it so much that I dug up my old HO trains from my first and second layouts, which I'd somehow hauled around with me for all those years. As i worked with my old HO and his new HO trains I learned that a lot had changed over the years. My old brass rails and couplers were antiques. I visited a train shop to get replacement couplers and parts/oil for the old locos and was amazed that progress in the hobby. I built my son a 4x8 table, as my Dad had for me, and put it in the garage with a dust cover. The layout was easier to set up than my old one had been because of the roadbed track.

I watched as my son made the same discoveries I'd made about trains. The fun, yes, and also the frustrations of a small layout in a dark, dusty environment. We visited the train shop from time to time and began looking longingly at the LGB displays. Eventually my wife bought me a starter set for my birthday and I added a few cars and track, including switches. We put it on the back deck and had fun with it.

A few years later I was given a large gift certificate to the train shop from some co-workers in appreciation of something I'd done, and used it to buy more/better large scale stuff including an LGB Mogul. I still didn't have room for the outdoor layout so we built a temporary one using sections of painted plywood. This worked okay and provided quite a bit of fun. Here's my son playing with it in the back yard:


However, I still dreamed of having the space to build a permanent layout. Alas, while our yard was sizable (9900 s.f.) by local standards, it was 100% full of kid play areas (as the above picture shows).

Eventually in 2002 my son, then 6, began setting up a ladder in the garage and climbing up to look at the Märklin layout that was in storage. He would lift up a corner of the dust cover and sit and gaze longingly at it for hours, literally. After this persisted I called a friend who came over and we took it down and got it going again, moving Daniel's 4x8 HO layout board into the vacated storage spot. Daniel loved it and I had fun with it too. We used it for several months until I decided to start the 4th layout, which I'll cover in my next "design influences" post.

So, what did I learn from all this kid interaction that influenced the design of my current layouts? Two things:

• Remember the COOL factor. Kids like things that are cool, and this is usually what attracted us to the hobby in the first place. But sometimes as adults we forget that.
  
  My son commented that he loved the Marklin layout because of the changing levels, the bridges over tracks, and the switches. He also loved the steam engine best because of the side rods. You know what? That's what I loved as a kid, too. But as an adult I was becoming overly influenced by others in the hobby who insisted on things like fidelity to the prototype and being as realistic as possible. In the process I tended to give up some of the "cool" things, as in: "they didn't have steam anymore in the year I model, so there are no steam engines on my layout" or "I love Famous-Passenger-Train-X, but I can't included it because it never stopped at the city I model". This isn't to say a pure prototype model railway isn't something great to acheive, but there is a balance. Both of the model RRs I'm working on now have plenty of "cool".



• Include kids in the experience. When kids experience joy with something that you have created you experience their joy too. I understand some model railroaders don't want kids near their layouts because kids admittedly can create a lot of hassles, and if not supervised can cause a lot of damage. But I am making my layouts very much kid accessible. Now this won't mean a free-for-all. I've shown the N-scale layout to my kids' friends and made sure they understood the "don't touch" rule before they even enter the layout room. At the same time, I also set up the train control system to make it easy for kids to participate. Finally, I made sure the lower level is at a kid friendly height. My own kids aren't all that interested any more in the indoor railroad (they love helping outdoor however, and 3 of them had a blast at last summer's Garden Railway convention), but they still participate, and will probably do more as we move to the scenery phase.

In my next post on design influences I'll talk about the 4th layout, which was a temporary layout for the purpose of learning N scale.

Outdoor model train scales

In the earlier post on gauge and scale I mentioned that the "large", outdoor scales range in size from 1:20.3 to 1:32. While these may seem like random numbers, there is a very logical reason behind them, dating back to the early history of model trains.

Some of the earliest model trains in the late 1800s were made by Märklin in Germany. They built three sizes of trains and named them "1", "2", and "3" gauge. All three were on the large size, reflecting the technology at the time. "1" gauge is 45 mm between the rails, about 1.77 inches.

When Lionel started making electric toy trains in the early 1900s in the U.S. they decided to name their gauge "0", pronounced "zero", because it was somewhat smaller than "1" gauge. However, people reading "0" (zero) thought it was the letter "oh", and so "O" has forever been the name of 1:48 scale. The smaller O scale trains quickly surpassed the larger 1 gauge trains in popularity because they took up less space. While "1" gauge trains continued to be produced in smaller quanitities, "2" and "3" stopped being produced.

Later in the 1930s Märklin came out with an even smaller scale, 1:87, and named it "half-oh", or "HO" for short (even though it was quite a bit bigger than half of 1:48). HO quickly leaped ahead of O in popularity, as many other manufacturers followed Märklin's lead. "1" became an almost forgotten gauge.

Fast forward to the late 1960s when a family named Lehman in Germany decided to build electric trains that could run outdoors. They chose "1" gauge track and named their new company LGB for Lehman Gross Bahn -- which translates literally to "Lehman Large Trains". For their initial line of trains they chose to model European prototypes that used a 1 meter narrow gauge. A 45 mm gauge track, when used to model a meter gauge prototype, yields a scale of 1:22.5. This soon became known informally as "G" scale. However, "G" was never officially recognized as a scale, and today people often mistakenly use the term "G" for any train running on "1" gauge track.

LGB trains were a hit, first in Europe and then in the states. In the 1970s LGB introduced more trains, including models of standard gauge European trains and 3-foot narrow gauge U.S. trains. LGB was vague about the scale of these new models, in part so that the cars from one size prototype wouldn't look out of place in the same train with others, and this resulted in a lot of confusion. (Today some modelers feel that LGB's failure to provide accurate scale info with their models ultimately contributed to their sales decline and their recent bankruptcy.)

In the 1990s and 2000s many other manufacturers entered the large scale train market and fortunately almost all of them provided specific scale info. For "1" gauge models based on a 3-foot U.S. narrow gauge prototype the scale of 1:20.3 is correct. The NMRA has recognized this as "F" scale . For "1" gauge models based on standard gauge the correct scale is 1:32, which is now recognized as "H" scale. It's easy to remember these letters because F-G-H are all "1" gauge scales, based on 3 ft gauge, 1 meter gauge, and standard gauge prototypes respectively.

Unfortunately, before H scale was established Aristocraft introduced a line of "1" gauge products based on standard gauge prototypes in 1:29 scale. As such the trains were somewhat larger than they should be given the wheelbase of the trains. Aristocraft chose 1:29 apparently because this allowed the LGB narrow gauge boxcars to look correctly proportioned next to Aristocraft product. USA Trains copied this practice, and their product line became very popular due to their lower prices and US prototypes, so other manufacturers followed their lead. Today large scale modelers now have to be aware that some standard gauge product is 1:29 scale and some is 1:32, and to try not to mix them because they will look funny together if you do.

Just to complete the confusion, a lot of the non-train models that are available for adding scenery to your outdoor layout are 1:24 scale, which kinda-sorta works with some of the other scales if you don't look too closely, or if you separate the 1:24 models from the trains visually.

One other point to note is that although all the "1" gauge trains will run on the same track, there are still separate lines of F, G, and H scale track. That's because while the rail gauge is the same, tie sizes vary greatly between scales.

Now, having said all of the above its worth noting that Garden railroaders tend to be a lot more relaxed than indoor modelers about prototypical accuracy. Many happily run trains of mixed scales. Others may run all their narrow gauge trains one day and all their standard gauge the next. And despite such sacreligious behavior they amazingly still get their layouts featured in Garden Railway magazine! :)

For my outdoor layout I have chosen a U.S. 3 foot narrow gauge prototype, so my scale is F (1:20.3). Actually, to be precise, my scale is Fn3, reflecting the 3 foot narrow gauge. However, the "n3" is usually not mentioned since virtually everyone in F scale is doing narrow gauge.

Design influences: third layout

I started my 3rd layout late in 1989, almost 9 years after my second layout was built and dismantled. I was newly married, and my wife, noting my intense interest in both real and model trains, suggested I build a layout. I immediately adopted her suggestion, of course, as I did not want to be disagreeable early in our marriage. ;)

Popular layout design theory holds that there are three decisions you need to make before you get started designing the layout: theme, scale and site, though not necessarily in that order. For my third layout the theme was a given -- European passenger trains. I'd moved to central Germany in 1987 and had traveled western Europe extensively for work and tourism while I was there. Europe had, and still has, a plethora of wonderful passenger rail. Furthermore, shops with European model trains were plentiful, with virtually one in every decent sized shopping district plus large model train departments in most of the big department stores. In 1989 I had one of each within 3 blocks of my apartment. Given that I was in the center of all this, and that I loved passenger trains, no other option was even considered.

As to scale, I was predisposed to HO but had to do some research before deciding. I visited a couple of local shops and found that German model trains were different in many ways from those in the U.S. In the U.S., with the special exception of Lionel Toy Trains, a wide variety of manufacturers will make interoperable equipment for the same scale. In Germany, at least back in 1989, modelers tended to stick predominantly to one manufacturer. I think this was mostly because the largest manufacturer, Märklin, set the tone with their distinct HO product line. Märklin HO has proprietary couplers and a unique 3-rail track system, with the third "rail" fairly well disguised as metal bumps in the center of the ties.

So the first question the train shop owners asked me was "which brand of model train are you using?" I hadn't decided, so in response I reviewed a few product catalogues and settled pretty quickly on Märklin HO. I suppose part of my rationale was the apparent quality of their product and the relative breadth of the their product line. But the main reason was that in 1988 Märklin had introduced their "Digital" line, which was what we now know as DCC. Such a product rollout was and example of the key advantage of a proprietary model train brand. While the rest of the model train industry would spend the next 15 years or so evolving the standards and practices to make DCC practical and universal, Märklin was able to provide all the necessary components all at once, out of the box. No messy decoder installs or debugging of weird timing problems between different manufacturers. It was literally plug-and play back in 1988.

Having decided on theme and scale I now needed to pick a site, and that was a bit of a challenge. We lived in a 61 square meter, one-bedroom apartment. Not small for two people, but not very accomodating for a model railroad. I knew the layout would need to be portable in sections, both because we would eventually move out of the apartment, and also because I would need to put it away in the storage locker when we entertained. I eventually settled on a 3x1 meter portable layout concept consisting of three 1x1 meter sections. This is roughly 32 square feet -- about the same as an American 4x8 layout, but somewhat longer and narrower.

With theme, scale and site decided I then needed a layout design. I quickly found that it was going to be very difficult to squeeze an interesting passenger layout into such a small space. When you start any layout design it's helpful to figure out the key constraints and requirements at the start, what the great layout designer John Armstrong called "Givens and Druthers". For me they were:

1. Train length. I wanted to run trains of up to 5 passenger cars. The longest train measured 160cm with the locomotive.


2. Curve radius. It was a given that any curves were going to be of the tightest possible operational radius, and hidden in tunnels because they would look so unrealistic. This turned out to be about 40cm radius if I recall correctly, or about 15".


3. Stations. Passenger train layouts need stations. At first I was open to a minimum of one station, either a through style or a stub terminal style. After sketching a few designs, though, I realized that I needed a minimum of two stations to keep it interesting, and ideally one of each style.


4. Realism. The setting should be at least possible, if not plausible. This implies that the trains would need to exit through a tunnel somewhere to go "off stage", which would represent the "rest of the world". I had not heard the term "staging" back then, but the requirement for staging was clear. It also meant that oval designs or twice-through-the-same scene designs were out of the question.

I sketched all kind of layouts but just couldn't find a solution that I liked. The best I could come up with was a layout with a 3-meter-long view block lengthwise down the middle. On one side would be the stub terminal, then the train would go through a curved tunnel to the other side where there would be a through tunnel. Then the train would go through another curved tunnel to an under-layout staging area.

But this design concept had at least three problems. First, the overall run for the train was very short, making it less interesting to operate. Second, there was the problem that trains would still be exiting the first station while simultaneously entering the second. Finally, this design requires walking around the layout to follow the train, which is acceptable in theory, but in practice is difficult given that Märklin did not yet have walk-around controls.

I bought some German layout books seeking inspiration, but found no answers. I dug out my old copy of the "101 Track Plans" book that I used for my second layout, but still nothing satisfied. I eventually got so frustrated that I seriously considered switching to N scale, even sketching some N scale plans for the same space. Finally I found my solution by looking "one last time" at a Märklin layout design book. Most of the Märklin layouts in that book eschewed realistic operations, but one design stood out:


To see why I liked this, ignore the logging and industrial elements in this picture and focus just on the layout of the main line. The railroad starts at the stub terminal at the top of drawing, which is at the top of the hill, then winds its way down slope, making two horseshoe turns with the second turn in a tunnel, and arrives at a through station. From there it goes into a tunnel that goes to "the rest of the world", a.k.a. "under layout staging".

I might not have seen the passenger possiblities here if my wife and I had not been making frequent visits to Switzerland, where I'd noted the following about Swiss mountain railroads: 1) The Swiss have a lot of tunnels, and often in places where Americans would have chosen a large cut; 2) There are a few mountain towns in Switzerland that are accessible only by train or hiking path; 3) There are some places where two stations are quite near each other, separated as much by elevation as by horizontal distance; and 4) compacted, complex trackwork is common throughout the Swiss mountains as they often have to squeeze track into small spaces.

So, I could see this track layout working with a Swiss mountain theme. The track distance between the two stations allows for a longer run that addresses the concerns stated earlier. The two stations would be separated mostly by elevation and in a mountain town that was accessible only by train. I would not include the industry shown on the Märklin drawing, but would allow a "goods track" at each station for local freight deliveries (what in America we would call a "team track"). For even more fun the theme would be a ski village in winter. And the whole layout could be viewed and operated from one side.

The next step was to compress the layout design from the 3.0x1.7 meter space shown in the drawing to my 3x1 meter space. This wasn't hard as I didn't need the space that was set aside for industry. As I drew the detailed design it I re-routed the main line and made a few changes, most significantly adding a turntable to the stub terminal. This was totally non-realistic as the Swiss converted to electrical railroads for their mountain tunnel lines very, very early (the first decade of the 1900s I believe), but I wanted the flexibility of running steam. I later gave the railroad a specific date of Boxing Day (day after Christmas), 1956, and planned to string electric catenary. The idea was that the catenary would be new, so new that the viewer couldn't tell whether it was yet operational. I could then run steam, diesel or electric depending on my whim.

I built the layout in early 1990 using a German language model railroad how-to book as a guide. The methodology they used worked, but I don't recommend it because it's not very conducive to later revisions of the layout. The Märklin turntable I'd included in the layout plans was announced but would not be available until 1992, so I ran trains without it for the first year. The digital system worked great, and I built a few models and a bit of scenery.

By 1991 I just left the layout in the storage locker, as moving it in and out had become a pain. In late 1991 I took a job in California, and in early 1992 we moved into a new house. The layout was setup in one of the bedrooms. This picture shows it shortly after things were unpacked and I had gotten the trains running:


Unfortunately, this amazingly is the only photo I have of the layout today. Alas, the angle is not good for seeing the track plan, the scenery is not in position, and there are even random items piled on the layout in places. I think I took this picture as part of a series showing each room in the house after move-in. Furthermore, the turntable was not yet in place. However, as it is the only photo I have I'll have to use it to describe the layout, and how it differed from the Märklin drawing that inspired it.

The top tier was the stub terminal -- this level had no slope. There were three tracks for passenger trains and one short track, on the side farthest from the camera, for goods cars. The space for the turntable and a few locomotive tracks was on the right -- I would add the turntable to the layout later in 1992. Two double-slip switches connected the turntable to the passenger tracks. There was an escape crossover near the end of the two longest passenger tracks, to allow for backing steam locomotives back to the turntable, turning them, and attaching them to the other end of the train for the return journey.

The middle tier was on a 4-5% grade connecting the two stations, with the left half of this tier in a tunnel. I added a siding to the middle tier between the curves, and this proved very useful in operations. The inspiration for adding a siding partially in a tunnel came from the line between Grindlewald and Wengen in Switzerland.

The lower tier was on a 1-2% grade with a two-track through terminal. A short goods track was also included on the left side. Curved Märklin switches were used at both sides of the lower tier so that the station tracks were long enough to accomodate the passenger trains.

The underneath staging level consisted of a double-track reverse loop. Because of Märklin's 3-rail system no auto-reverse mechanism was needed. Staging could accomodate up to 4 trains.

Operations consisted of a tight holiday schedule of regional, local, and worker passenger trains, with two runs for goods cars placed at gaps in the schedule. To add operational interest special events, such as late trains or a non-functioning engine, were introduced at random intervals.

I continued to run trains and enhance the layout occasionally through the end of 1993, when our first child, Paige, was born. During that time I'd converted the layout from being in 3 sections to one large section, in order to make continuing construction easier. Work then essentially stopped on the layout until late 1995, when the arrival of our second child, Daniel, meant the layout had to move into storage. I built a special holding platform for it high in the garage and packed it all away as carefully as I could, and it sat there for many years.

In early 2002 I found that my train-obsessed son was climbing up a ladder in the garage, lifting the layout dust cover, and spending hours staring at the the layout. He had his own HO trains (supplemented by my old American HO trains that had been converted with modern couplers) on an oval layout on a flat board. But he was fascinated by the mountain layout with the slopes and bridges. We decided to swap the two layouts -- the Märklin one went in the garage spot where his had been, and his went where the Märklin one had been stored. We then revived the Märklin layout and ran trains for several months.

It all ended when I decided to start a new layout in N scale. The Märklin layout went back into storage and was dismantled for our move in 2005. I have a tinge of regret about that, but I'd realized that I never was going to have time to finish the Märklin layout given a) my new interests in N scale and large scale and b) that I'd lost interest in Märklin 3-rail.

So, what were the lessons learned from the 3rd layout?

1. Yes, I love passenger trains. More specifically, I loved the drama of the trains coming in and out of the stub terminal and crossing over the double-slip switches. The stub terminal was my favorite part of the layout, especially with the abundance of operational possibilities after the turntable was added.
2. Double track is cool. This layout was single track operationally, although with two stations and a siding most of the actual main route was double track. I did this because single track is recommended for layouts because it increases operations activity due to having to accomodate meets between trains in opposite directions. But as I looked at the staging part of the layout, with the double-track curve, there was something about that "boulevard of steel" that made me want to emulate that on the main line with my next layout.
3. Digital is cool. Märklin digital, less so. For one it's ridiculously expensive, and for another many of the operations were very difficult due to limitations of Märklin controls.
4. I can do without turntables. Oh, they are fun and cool to look at, but the huge amount of work required makes me question the fun/work ratio. I haven't planned one since, although my outdoor layout will probably have two for prototype reasons.
5. I'm ready for a really big layout. After this layout was done I felt I'd done as much as I could with small space compromises, and that what I really wanted were long trains over very long runs and curves that weren't so tight that they had to be hidden in tunnels.
6. I want more realism than what this layout offered. Given the space I had it was the best I could do, but some of the pretenses required to create interesting operations were really stretching the term "realistic". Another reason to go big with the next layout.
7. I discovered that my modeling interests tend to be influenced heavily by where I live. When I built this layout I was surrounded by European trains and couldn't imagine modeling anything else. I think that part of the reason my interest waned in 1994, apart from the thrill of a baby in the house, was that European trains were becoming a distant memory to me -- and when I revived the layout in 2002 the European trains seemed no more realistic to me than the Thomas the Tank Engine trains my kids had. However, at that same time I'd become very interested in local railroads like the Southern Pacific and the old narrow gauge South Pacific Coast.

All of these lessons would factor into my current layout. Unfortunately, in 2002 I still didn't have the space to go "big", so my 4th layout would have to incorporate some, but not all, of these learnings.