Digitrax Frustrations: Known bugs in DS64 and DCS100

 tl;dr:

1. It's a good practice to read all Digitrax tech notes on their website for a given component before doing anything with it.  Tons of "this bug is feature" notes.
2. There is a known intermittent DS64 bug which on startup randomly switches some turnouts.  This has been known since it came out circa 15 years ago and no solution.  The configuration options to prevent this don't actually work.  (Later edit: possible solution found, see start of main text)
3. The only workaround is to create a "super route" that resets all turnouts to what you want their defaults to be.
4. You can't do the "super route" with a DCS100 or 2000 command station route because of an undocumented feature that they don't pass the routes via Loconet.
5. You can waste days messing around with crap like this.

Switch machine standards

This post describes the procedure and standards I use for installing Tortoise switch machines on the main layout. This is the first of two related posts -- the next post will cover the switch wiring standards.

As I write this I have successfully installed 12 Tortoises on the layout, all driven by Digitrax DS64s. The photos in this post were taken of the last two Tortoises I installed.

This process is not by any means fast. It takes me at least an hour per switch. I don't claim this is the best process, but it works, and it's the product of lots of learning, research, and trial-and-error.

Background: The Tortoise

The normal Tortoise installation position is shown in the picture below, which is copied from the Tortoise instruction sheet:

This photo is a bit hard to decipher because it is in black-and-white, but the components are all there. At the top you can see the switch (they use HO scale in this picture, but the same machine works for N and other scales too). The switch is on top of roadbed, which looks white in this picture, and that in turn is on top of a piece of plywood subroadbed. There is also a shaft drilled through the cork roadbed and plywood subroadbed. The Tortoise is attached underneath the plywood. A non-electrical metal wire, which I will call a "driving wire", links the Tortoise to the switch through the shaft. The driving wire goes through a “fulcrum”, or pivot point, which is piece of plastic with a small hole for the wire near the top of the Tortoise in this picture, then down to a screw near the bottom that holds the wire to the gears. When the gear shifts from one side to the other, the wire is moved and the switch above will move to the opposite side.

This is a simple but cool mechanism. Because of different scales and different thicknesses of subroadbed, the span of the “throw” at the top of the driving wire (that is, the distance the wire covers at the top when going from one side to the other) can be adjusted by moving the fulcrum up and down. The instructions also say that you can substitute a larger gauge wire if you like, and this can be useful in some situations.

Extending out of the bottom of the Tortoise in this picture is a circuit board for 8 electrical connections. The Tortoise is driven by a low DC voltage using the 1st and 8th connections. To “throw” the switch you simply reverse the polarity of the DC voltage being supplied, and that causes the gear to switch sides. Once the gear has gone all the way to one side the motor stalls. It can still receive power without causing problems, and depending on your situation you might want to keep the power constant to be sure the point rails are held against the side rails.

The other 6 connections on the circuit board are linked to two internal SPDT switches, which are switched whenever the main switch is thrown. The most common uses for these are to provide switched track power to the frog rails and to wire lighted indicators for a switch board. I will be using both of these functions, but this post only describes the frog wiring as I haven’t set up the light boards yet.

A sideways installation: concept

I chose not to install my Tortoises as described above, for two reasons. First, you’ll notice the Tortoise sticks out quite a ways under the layout – almost 4” when you consider the wiring attached to the circuit board. I simply won’t have that much available space under the upper deck, nor at certain parts of the lower deck (such as above the power cabinet). Furthermore, even where there is 4" of vertical space I prefer not to have the Tortoise taking up that much head room in the under-layout crawl area.

Second, on the lower deck of my layout there are many places where the thickness of the foam subroadbed plus the underlying plywood is as much as 2 ¾”. This means the driving wire has to be extra long, which is not by itself a problem. But it also means that the span of the “throw” of the end of the driving wire is huge, even if the fulcrum is moved to the absolute top of the Tortoise. Add in the fact that I’m in N scale, and what this means is that with a normal Tortoise installation the “throw” for the wire is 3x the distance needed to move the turnout (switch) from one side to the other. In practice this is still workable, as the wire is bendable. But the downside is the aesthetics. One of the key benefits of the Tortoise is that your switches move in slow motion, like the prototype. At a typical DC voltage the time it takes to move a switch from one side to the other is about 3 seconds. However, when the “throw” span is 3x the width needed to move the switch, what happens is that the switch is moved in 1/3rd the time, or about 1 second, and that means the appearance is way too fast.

Both of these are common problems and thus there are many proven solutions. The Circuitron people even sell special sideways Tortoise mounting kit to address the first problem (but not the second). A while ago I ran across a link to this model railroading news letter where on page 8 the author describes his procedure for sideways mounting. As I studied it I realized that not only was this cheaper than the official sideways mounting kit, it also had the added benefit of addressing the second problem (although that was not the author’s intent) because of the geometry of the two wires and fulcrums.

The procedure I use is copied from his, making adaptations only because I used different materials that were more readily available. After successfully testing this with one switch, I modified the remaining 13 Tortoises that I had on hand as shown in this picture:

My goal in the modification of the Tortoise is to prepare it for an installation that looks something like this, viewed from underneath the layout:


Note that both Tortoises in this picture are mounted sideways. The wire that drives the switch still runs through a vertical shaft in the plywood, but now there are two wires and two fulcrums.
The rest of this post describes how to set up this installation.

Preparing the Tortoise

1) You are going to glue two pieces of styrene to each Tortoise. In preparation, you will file down Tortoise plastic “shell” slightly just to make sure there is a smooth surface to glue to. I first used a hobby file, but then went to a normal sized metal file as it was quicker. The first place you need to file is what will be the “top” of the Tortoise when it is installed – this is the side opposite the side with the gear. You probably have to take off the round sticker that the inspector put on it and then need to file down the “bump” down the middle where the two plastic pieces of shell were joined. Do so for the whole side. The second place you need to file is the side that is the “top” in a normal installation. Again, file down the bump in the middle.

2) For what will be the “top” of the Tortoise you will want to attach a piece of .030” styrene about 2 7/8” x 2 3/4”. This styrene will act as a mounting plate. As per the picture above, you see there is a plate of white styrene attached to the top of the Tortoise with glue, and the plate is screwed to the plywood to mount the Tortoise. I bought some large sheets of .030” styrene in bulk and cut them with a plastic cutter. Thicker styrene can also work – I would not recommend thinner. Once cut, I attach the styrene using common super glue, which dries very fast and holds strong.

3) You’ll need a second, smaller piece of styrene to act as the second fulcrum. In the picture above this is the piece of white styrene at the very left of the photo, attached to the Tortoise very near the plywood, and with the driving wire running through it. For this I used .040” styrene, cut to 1.5” x 1/2"”, and used super glue again to attach it to the Tortoise. It’s a good idea to drill the hole before attaching. I placed the hole in the center, lengthwise, and about 1/8" from the end (widthwise). The hole should be big enough for the wire, and after the hole is made you probably want to tilt the drill at an angle and move it in a circle to provide an angled cut so that the wire can tilt as the switch is thrown.

4) For driving wire some people recommend .025 piano wire. I use 18 gauge wire that I found at the local Michael's art supply store in the floral section. It's intended to serve as a stem for fake flowers, but it's very cheap, is available in bulk packages, is perfectly straight until you bend it, and can be cut easily. It's thicker and stiffer than the wire which comes with the Tortoise, which is an advantage, so I use it for both of the wires in each installation and save the stock wire for some unknown future use. The wire lengths should be cut to fit your installation, with some extra left over just in case.

If you use the thicker wire you'll need to drill larger holes in the Tortoise fulcrum and in the slot where the wire slides into the gear. I recommend buying a small hobbyist hand drill with an assortment of small bits -- you can use this for all kinds of model projects, and the hand drill is easier to control than a power drill. I choose a bit that is exactly the size needed for the 18 gauge wire.

For the gear slot, I use hobby pliers to hold the black plastic gear while drilling -- this prevents possibly damage by pressing too hard onto it. Ditto for when the screw is added. When that wire is in place add the green fulcrum, putting the wire through it.

5) Then you join the driving wires, one each for the styrene fulcrum you added and the green fulcrum that came with the Tortoise. There are many options here, but the easiest I found is to use a short (1/2" or so) length of chunk of retangular, tube styrene available at any decent model train shop (Evergreen Scale Models #259, .250 x .375"). I drill cross holes in each direction and put the wires through. While there may seem to be a lot of slack in this set up, in practice the first wire moves the second like clockwork.

6) For final touches, first add 4 holes to the edges of the mounting piece of styrene and pre-set 4 screws (I use #6, 5/8"). Then I add a label for the switch number. This shows a Tortoise where everything is ready for installation. Note it is upside down and the second driving wire isn't in the picture -- that will get added during installation:


Preparing the Switch

There are three things you need to do to prepare the switch for Tortoise installation (or possibly 1 or 2, depending on your type of track). It is easier if you do these before you install the switch on the layout, but alas I'd already installed these switches, so I had to do these things after the fact.

First, here is an example of two Peco code 55 switches, installed in 2006 and still on the original AMI roadbed:


So here's the modifications that I make:

1) First, I connect a feeder wire to the frog rails. I described this issue with "Electrofrog" or "Live Frog" switches last year. In my case, I had hoped that I could avoid having to make the extra effort to add a separate feeder wire the frog rails, but my experience operating the layout proved that in the absense of a separate feeder wire, the frogs frequently lose power due to dirt between the point and outside rails. You can correct this immediately by cleaning the rail contact points, but on a large layout you have to do this a lot during operating sessions, so it quickly becomes tedious.

Adding a frog wire retroactively to an installed Peco code 55 switch is a challenge, but doable. There is a connecting frog wire hidden underneath the switch. I found that I could access it from the outside rail of the straight route, between the 2nd and 3rd tie from the end. I used an eXacto knife to first cut out some roadbed, then cut the plastic under the rail, and then "dug" a bit into the under-rail plastic until I caught the wire on the end of the knife. I would then pull the wire out just enough for it to be visible. At that point I would strip about 1/2" of insulation off of a 22 gauge solid green wire, bend the end of the wire into a hook, and use it to "hook" the exposed frog wire. Once hooked I'd use small hobby pliers to clamp the wires together, then solder them, then drill a hole in the plywood for the green wire. The end result is a hidden feeder wire connecting to the frog rails on one end and sticking underneath the layout on the other end.

2) Peco switches have built in springs that force the switch to one side or the other. This is a nice feature in the absence of a separate switch machine. However, when using a slow-motion Tortoise the spring needs to be removed.

The spring is located right at the end of the point rails. You will see two metal tabs on the plastic part between the rails that spans two ties. Use and eXacto knife or similar to pry these up, then remove the plastic tab in the middle. Then push the metal tabs down so that you can remove the piece of metal that includes thow tabs. Finally, the spring itself is now visable. Pull it out with hobby pliers or a tweezer. You're done.

3) Finally, you need a hole for the driving wire that will link the switch to the Tortoise. I use the hand drill mentioned earlier. This hole should be in the large tie that drives the movement of the point rails, and I prefer putting the hole in the exact center of the tie between the rails, rather than, say, on the part of the tie on side of the rails. It just seems to work better that way.

First, I use a small drill bit to create a pilot hole, then a larger drill bit that is the exact size of the driving wire. Be very careful, as too much downward pressure can damage the switch.

4) One other thing you'll need is to drill the shaft through the subroadbed for the switch machine wire. I use a 3/8" bit, and am sure to clean the shaft of debris before installing the switch.

Here is a switch which has had all of the above steps completed, and even has a driving wire in the wire hole. At this point the switch machine below is not connected, so the wire has been slightly bent at the top to prevent it from falling through:


Installing the Tortoise

With the switch and Tortoise both prepared we are ready to connect everything up. Depending on the space available underneath this can require some real physical contortion to reach everything. To the degree possible try to provide adequate space and light. I use at least two cheap "clamp" worklights available at hardware stores. It's good to have two to provide lighting from different directions so that you avoid shadows.

1) Prepare the space.

Make sure there is a spot under the layout clear of wires and other obstacles. Here is an example of such a space:


On the left side of the picture you can see the bottom of the shaft for the driving wire, and the wire itself hanging down from the switch. Next to that hole is a white shelf support bar -- because of that we won't be able to install the Tortoise to the left of this shaft, we'll need to do it to the right of the shaft. On the right side of the picture you see the green feeder wire from the frog. In the middle of the picture is the red-and-black power bus. This is near the intended location of the Tortoise, but not in the way.

The Tortoise itself has to be positioned so that the movement of the switch wire is perpendicular to the switch itself.

2) Connect the Tortoise to the plywood.

Here's a picture showing this step completed:


This is a pretty simple step conceptually. Position the Tortoise such that the driving wire is through the styrene fulcrum (see left of picture) and that the fulcrum hole is at the center of the shaft. This gives the wire maximum movement potential -- if the hole is too near the sides of the shaft the you may find the switch doesn't move well. Also make sure the Tortoise is lengthwise positioned in the same direction of the switch itself -- this is to make sure that the wire movement is perpendicular to the switch. Then drill the 4 screws in and you are done.

In practice this is tricky. I usually put in the first two screws manually, at least part of the way, to make sure they go in straight and don't shift the location of the Tortoise. Then I use a power drill on slow speed setting with an extra long drill bit to keep the screws going in straight.

3) Connect the frog wire.

Here is a Tortoise with just the one frog wire attached, not yet soldered:


There are two options for adding wires to the Tortoise circuit board. One is to buy a 3rd party "slide on edge connector" which have wire clips on one side and a slot for the whole unit to slide on the tortoise circuit board on the other side. This is the smart way to do it, as it saves difficult soldering and allows for easy changes later.

So, since that is the smart way, naturally I do it the other way. Mostly out of trying to save money where I can. I solder the connections. Now, this is quite tricky but I've gotten so I do it quickly and reliably. And I figure that if I need to make changes later I can do so at the other, non-soldered, end of the wire.

After I have the Tortoise in place I think of the circuit board as having slots numbered 1-8 from left to right, from the point of view where you are sitting looking at the board directly (as in the above photo). In this case slots 1 and 8 will be used for the switch power from the DS64. I connect those wires last because it is easier to solder the inside slots first. Slots 5-7 will be used in the future for the switch board lights, so I don't talk about them in this post. Slots 2-4 are for powering the frog.

Slot 4 is the frog wire. This is the unswitched side of the connection, as shown in the internal Tortoise SPDT diagram below (taken from the Tortoise instructions):


I'll have more to say about the above diagram on the next step. For now, the point is that slot 4 is always for the green frog feeder wire.

Attaching and soldering is the same process for each wire. First, I strip about 3/8" of insulation from the end of the wire. The wire is then routed through the hole and, using hobby pliers, the wire is bent as shown in the picture above so that it forms a "U" shape and clamps onto the circuit board. You want to have only a small amount of wire extending above the board, and you want to make sure that there is no chance that any two wires above the board will touch each other. Below the board there is a thin, narrow strip metal for connectivity, so you want to run the wire along that metal strip.

Once in place, I use a soldering iron at 40W (the 20W setting doesn't work as well for this application). I place the flat end of the iron blade on one side of the wire and make sure it is touching the circuit board metal strip, then apply solder from the other side of the wire. The whole process takes only a few seconds -- as soon as the solder is applied I remove the solder source and the iron. The solder will tend to bind to the metal, not the insulation between the metal strips, if you are spartan with the solder there should be no shorts yet the connection should be solid.

4) Connect the track power wires

This picture shows the same Tortoise after the track power wires have been connected:


It's not clear from the picture, but the red track wire has gone to slot 2, the black to slot 3. The track wires are connected to one of the terminals on the power bus, as described in earlier posts on wiring standards.

The biggest challenge at this point is figuring out which track polarity goes to which of the two slots #2 and #3. There is no simple rule of thumb. It depends on the orientation of the switch itself and the orientation of the Tortoise. The only solution I found that works is a complicated procedure. I first look at the switch from above and mentally identify which rail is "red" and which is "black". Then I note whether we want the frog rails to be "black" or "red" when the switch is set to the "normal" or "straight" route. In that case the frog rails should be the same polarity as the outside rail from the diverging route.

Then I mentally note whether, in the "normal" position, the switch is set toward the wall or away from the wall. Thus, at that point I might be thinking "switch set toward wall, polarity black", for example.

Then I climb under the layout and position myself so I am looking at the Tortoise from the side of the circuit board. Let's say, from that point of view, that the "toward wall" position matches the left side of the Tortoise. So I will now say, "switch on left side, polarity black".

Now I look at the internal Tortoise SPDT diagram shown above in the previous step. At the bottom of that I have manually drawn in two boxes and a line connecting them. This represents the two possible positions of the switch. The box on the left is filled in, the box on the right is hollow. So what this says to me is that when the switch is on the left, the internal SPDT switches will be in the position shown in that diagram. When the switch is on the right, the internal SPDT switches will be in the opposite position.

And from this, I know that if "left side, polarity black", then if the switch is to the left slide, then slot 4 (frog) will connect to slot 3, so slot 3 should be the black wire.

Then after doing all that I repeat the mental exercise to confirm the result, then I attach and solder the wires.

After doing this for 11 Tortoises I've found it works every time. The only time I made an error in polarity was when I tried to short cut the process with a "rule of thumb", copying the wiring on a nearby Tortoise, but missing a detail so I made an error.

5) Connect the switch power wires

This picture shows the same Tortoise after the power wires were connected to slots 1 and 8:


One thing that might be confusing is that there are two pairs of white power wires -- one coming from above, and another extending below. The reason is that the Tortoise in this picture is one of a pair of Tortoises that drive a crossover. Crossover switches have the unique attribute that they should always switch together. That is, it makes sense only if both switches are set to "diverge" (so that a train can crossover between the dual tracks) or "straight" (so that trains can pass each other on the two tracks). So, in this case we wire the power for both Tortoises from the same DS64 switch slot, saving a switch slot and simplifying the control.

Therefore, the second set of white power wires are hanging down in this photo only temporarily. They will soon be connected to slots 1 and 8 on the paired Tortoise.

6) Connect the Tortoise driving wires

This photo is a repeat of the photo at the beginning of the post, and shows the paired Tortoises all set up:


You'll see that the driving wires are now connected using the piece of rectangular styrene tube. Back during the Tortoise preparation phase I drilled holes in the piece of tube so that perpendicular driving wires could go through both ends. Now the driving wires are routed through the holes.

It's worth remembering that the driving wire which goes to the switch will not be supported from above after this installation is complete. Therefore, in order to prevent it from sliding down and falling out, we need to support it from below, This is done by bending the bottom part of the wire around and using pliers to clamp it onto the rectangular styrene "connector".

7) Testing and tuning

Everything is in place but there is still quite a bit of testing left to do.

The first tests I run by powering up the DCC command station but not adding track power. The first test is simply to see if the DS64 actually drives the Tortoise using the switch address we thought we programed. Note that you may not see the switch actually move at this point (although it's better if you do), however, if you see the Tortoise switch gear move in response to the command then the test passes. If you have paired Tortoises, both must move, and their movement must be coordinated (so that both switches are either diverge or straight at all times). If this fails you need to check that the address is correct and then that the wiring is correct. (Or, if this is the first usage of that DS64, you need to verify that it is getting power and Loconet correctly.)

The second test is to make sure that the DS64 "thrown" and "closed" positions match that of the switch. If not the simple solution is to reverse the two wires that connect to the DS64. In fact, although it is possible to reason out in advance which switch power wire should go to which DS64 slot, in this case it's not worth the bother. I just connect the wires to the two DS64 slots randomly and half the time I end up having to undo and reverse them them -- a process that takes less than a minute. (Note: the reason I don't use the same process for the frog wires is that with frog wires we are dealing with soldered connections and the power test takes longer run.)

The third test is tuning the switch. Ideally as soon as the Tortoise gears starts moving the point rails will start to move from one closure rail to the other -- and get to the other closure rail just as the Tortoise completes the movement. You don't want the point rail to not reach the closure rail, obviously, but you also don't want it to get to the closure rail too soon either, mostly for aesthetics as noted earlier.

One adjustment is to move the green fulcrum on the Tortoise to increase or degress the span of the driving wire movement. The other adjustment is to slightly bend the wire if the switch is favoring one side or the other. This adjustment takes practice, and the first time you try it you may decide you need to start afresh with a new wire after too much bending. However, once you get familiar with the process this adjustment is usually completed and tested very quickly.

Once the switch itself has been tested for correct connections and movement you can remove the top of the driving wire that was sticking out the the switch hole. Thus the switch will end up looking like this:


Note that you can barely see the end of the metal wire in the middle of the switch tie. After adding scenic treatment this wire will be completely hidden.

The final test is the power to the frog. For this you turn the track power on. There are two tests. The first is to see if the polarity is correct. If not you'll probably know as soon as you turn the track on because the frog will short, as the point will be touching the wrong rail. However, just in case the short is masked by some dirt between the point and closure rails, also test with a voltmeter on an A/C setting.

The second test is to make sure the frog is getting power separately from the point-closure rail connection. That is, test to verify that the frog feeder and red/black track power wires you connected to the Tortoise are actually routing power. Using the voltmeter on the A/C setting, first test to see what normal track voltage is between two nearby rails. (For my layout, it's usually 12.6V or so, which is correct for Digitrax on the N scale setting.) Then put one lead on the frog, one lead on a nearby rail of opposite polarity, and manually move the switch so that neither point is touching a closure rail. The voltage should stay the same -- if not the frog feeder connection is either tenuous or non-existent. Throw the switch and repeat again, to verify this works with both polarities.

Now you are done. This post didn't cover the wiring standards or the programming standards for the DS64. I'll cover that in my next standards post.

3 weeks on

Wow, already almost 3 weeks since my post describing my current project, automated switches for part of the main layout. And over 2 weeks since my last update on the project. Well, progress is going well, although the whole project will probably take twice as long as I'd originally hoped. This is, alas, normal for me. I've learned that when working on any project I should double the time I estimate it will take, as that usually is accurate.

So, if we go back to that original post from almost 3 weeks ago, here's where I am on the various tasks in this project:

1) Redoing the wiring for that section of the layout to match the new wiring standards. Completed on March 18th, as noted in the last post.

2) Installing (or in two cases, re-installing) and tuning Tortoise switch machines for 12 switches. 6 of the 12 switches are now in place and running. The other 6 are expected to be fairly straightforward, but they still take almost an hour apiece.

3) Appending feeder wires to the 12 switch frogs, and connecting them to the main power busses through an internal Tortoise SPDT switch. Initially figuring out how to append feeder wire to the frogs of installed switches was a real pain. Eventually, maybe on the 4th or 5th switch, I figure out a simple process. I use an Xacto knife, very fine, sharp, and narrow point, to dig out the underside of the plastic between the 3rd and 4th ties from the end on the outside of the diverging route. Once the plastic is out of the way I can dig out the hidden frog wire. I then link the end of a 22 gauge green wire to the frog wire, tighten the link with needle nose pliers, solder, and use a drill to make a hole for the frog wire under the layout. The whole process takes less time than for me to type this. This has been done for all the remaining switches. Of course, I still have to wire the Tortoise SPDT switches to the track power busses for the final 6 switches, as part of their install process.

4) Ordering one more Digitrax DS64, and installing and configuring two DS64s to drive the switch machines. Because 8 of the 12 switches are in crossover pairs only two DS64s, capable of controlling 8 separate switches, will be needed. All done, but boy it took a lot of research and testing to figure out how to configure the DS64s. More on this later.

5) Setting the standard for DS64 power, and installing a DS64 power bus. All done, but took longer than expected. More on this later.

6) Setting the numbering standards for the DS64s. All done, see comments above.

7) Settling on the method and design of the fascia switch panels. Have tried various materials, but have not settled on the final design. Will do so after all 12 switches are automated.

8) Building and installing 4 fascia switch panels. See comment above.

9) Setting the standard for powering the switch panel lights, and installing the power bus for same. See comment above.

10) Wiring switch panel lights, using the other internal Tortoise SPDT switch. See comment above.

So, lots done, and have learned a ton along the way. Hope to complete by next weekend.

Towards Automated Switches

My goal is to have complete switch automation for the section of the SAMR line on the main layout -- the only part of the main layout that gets regular use now -- by the weekend after next (March 27th). This will require:

1. Redoing the wiring for that section of the layout to match the new wiring standards.


2. Installing (or in two cases, re-installing) and tuning Tortoise switch machines for 12 switches.


3. Appending feeder wires to the 12 switch frogs, and connecting them to the main power busses through an internal Tortoise SPDT switch.


4. Ordering one more Digitrax DS64, and installing and configuring two DS64s to drive the switch machines. Because 8 of the 12 switches are in crossover pairs only two DS64s, capable of controlling 8 separate switches, will be needed.


5. Setting the standard for DS64 power, and installing a DS64 power bus.


6. Setting the numbering standards for the DS64s.


7. Settling on the method and design of the fascia switch panels.


8. Building and installing 4 fascia switch panels.


9. Setting the standard for powering the switch panel lights, and installing the power bus for same.


10. Wiring switch panel lights, using the other internal Tortoise SPDT switch.

So far I've verified that I can append a feeder wire to the frog of installed Peco switches using the exposed frog wire underneath the switch, and have attached two such wires. I've also settled on the power district boundaries for the lower deck and am about 45% through rewiring power district 2, which is the only PD needed for this project.

I hope to complete the rewiring tomorrow (Tuesday) and then install and tune two Tortoises on Wednesday. This may take longer as I'm trying a new method. I should also send in the order for the next DS64 tomorrow so that I can have it by this time next week.

All in all this is a good goal to have now. It focuses my work on a single, tangible goal (I've tended to be a bit scattered in my efforts lately, as the previous post demonstrates). Furthermore, once done the change will yield an immediate boost to the fun factor of operating the layout. And, finally, once done I'll have resolved quite a few open layout implementation issues, which should speed up subsequent construction.

After this goal is accomplished I'll focus on connecting the middle tier of staging to the main layout.

Addendum to Atlas Switch Prep Procedure

Last spring I wrote a post on how I prepare Atlas code 80 #6 switches for use in staging. As I was finishing up the middle tier I ran out of the switches I'd bought back in 2006 and started using the switches I bought late last year.

I am happy to report that Atlas has improved the switches since 2006. The frog is a lot cleaner and the area where the point rails meet the closing rails (the red circle in that post) seems to have been re-engineered to be almost perfect out-of-the-box. I found that switch prep was a lot smoother as filing was not needed for those areas.

The other huge plus is that the straight switch rail is now nearly straight, instead of being slightly curved away from the diverging route.

Unfortunately I also found that the outside point rail doesn't seem to close as nicely against the outside rail (the green circle in the previous post). Previously I rarely saw a problem with these, but now I may need to file these down in most cases.

Still, the net is quite an improvement.

Frogs: Dead or Alive

A "frog" is the part of a switch or crossing where rails from separate tracks meet. In model railroading, frogs can be of two types: "insulated" (a.k.a. "dead", "plastic", or "insulfrogs") and "live" (a.k.a. "metal", or "electrofrogs").

Different brands/lines of N scale switches either have live or dead frogs, or in the case of Peco code 80, both. The difference is important enough that I'll refer to it a few times in future posts, so I'm covering it as a separate post here.

Here is a diagram of a switch with an insulated frog (yes, I made this myself):




The parts in the center colored in black are plastic -- or any other non-conductive material. The rails on the top (blue) are one polarity, no matter which way the switch is set, and the rails on the bottom (red) are the other. In order to keep the rails powered correctly the switch will have hidden wires, usually underneath the switch ties, connecting the rails as shown in the dotted lines.

By comparison, here is a diagram of a switch with a live frog:



All the rails, including the frog, are metal. Even though there is an apparent electrical gap between the rails at the frog itself, they are electrically connected across that gap.

Electrical power distribution is a bit non-obvious for live frog switches. For the moment, ignore the box on the right of the diagram labeled "SPDT" and the lines connected to the box. When you open a live frog switch out of the box the SPDT box won't be there. Instead, in the out-of-the-box situation the frog rails and all the inner rails will get their power from where the rail point touches the outside rail (in this diagram look immediately above the word "Rails" in red). Thus, when the switch is thrown the frog and inner rails will switch polarity from red to blue or vice versa.

The potential problem is that the electrical connection between the point and side rails can be tenuous -- and can get worse over time with dirt or corrosion. Many modelers choose to supplement the power to the frog and inner rails using an SPDT switch, as shown in the diagram -- and often this SPDT is built into a switch motor such as the Tortoise or even with a manual switch controller like the Blue Point.

The other issue is that the live frog switch always has both rails in the non-selected direction at the same polarity. Now, this can be useful in the DC world as a means of controlling multiple engines on the layout. A spur or single-ended siding that is attached to this switch gets no power unless the switch is set pointing in that direction. This function is called "power routing" and thus an alternate name for live frog switches is "power routing switches". (Note that the corresponding alternate name for dead frog switches is "all live" switches -- meaning every direction has both power polarities -- but the use of the term "all live" for a "dead frog" switch is so confusing that I avoid it.)

For most DCC layouts, which already have multiple engine capability, power routing is useless. DCC operators prefer the ability to move their engine on the spur or siding for tasks like car positioning -- even if the switch is set against them. Thus, DCC modelers will tend to run separate wire feeders to all track that is attached to the live frog switches, then add insulated gaps next to the frog rails to prevent shorts.

Except for power routing are there any other advantages to live frog switches? Well, there are two. First, they can be more operationally reliable. This is because the insulated frog creates a power gap when one of the wheels of an axle is in contact with it. With most modern locomotives that get power via all wheels this is not a problem, but with older locomotives or sometimes with short switchers with dirty wheels this can cause engine stalls. This can be easily solved by keeping wheels clean.

The second advantage is that the all-metal frog looks more realistic than plastic frog switches, even after they are painted and weathered. In a well maintained DCC layout this is your only real advantage of live frog switches.

So, yes, if you've followed this far you've realized that live frog switches have one advantage -- appearance -- and yet each live frog switch requires the addition of an SPDT switch, one extra feeder, and two insulated gaps. So is the hassle of all that extra work worth the marginally better appearance?

Unfortunately, many of us don't get the choice. If you choose code 55 rail all the switches have live frogs. Which is why my main layout is full of live frog switches.

(not so) Secret Codes

In past posts I've mentioned Code 80 and Code 55 track. In model railroading, "Code xx" simply means the height of the rail above the top of the ties (a.k.a. "sleepers" in the British Commonwealth) in thousandths of an inch. For example: Code 80 track has 0.080" high rails.

"Why should I care about rail height?", you may ask. And many model railroaders happily build their layouts without ever worrying about rail height. However, it's just one more aspect of realism that a modeler may or may not be concerned about.

The problem is that most model train track has rails that are ridiculously big, and although most people don't notice at first glance, if you are looking at a detailed model of a railroad scene the oversize rail can often ruin the illusion.

In the prototype (a.k.a. "real life"), modern rails in the U.S. tend to all share the same flat-bottomed profile, as shown at the link. However, rail sizes can vary greatly. By convention, the rail size metric used is "pounds per yard" of rail. At one extreme, the early DRG narrow gauge lines used 30 lb. rail -- which is about 3 1/8" in height. At the other extreme the Pennsylvania Railroad (PRR) once used 155 lb rail for their main lines -- the heaviest rail in common use, and about 8" in height. Modern class 1 (the busiest main lines) rail tends to be in the 100-132 lb range (6-7 1/8" high), although some heavier rail (140 lb) is starting to be used. It's typical for a railroad to mix rail sizes -- sidings, spurs, branches and yards often have smaller rail -- often 80-90 lb or less.

How does that compare to the model? Well, in N (1:160) scale Code 80 was long the N scale standard, and is still the most commonly used rail. Code 80 is equivalent to over 13" high rail -- about double the size of a modern main line. Code 55 is now the preferred rail for N scalers more interested in the details, but even that translates to 8.8" rail height -- bigger even than the PRR. Code 40 track is available for those that want absolute accuracy, as code 40 is equivalent to about 6.4" high track (roughly 110 lbs/yard), but if you use code 40 you have to hand build your own switches. Some modelers choose code 55 for the main lines and code 40 for spurs and sidings.

How much difference does it make? Well, compare a photo of a prototype locomotive to its N scale equivalent sitting on code 80 track and you'll notice the difference right away -- of course, that's probably because you'll be looking for it. In practice, most people don't notice, especially if you "weather" your track by painting a rust color on the sides of the rails and do a good job with the ties and ballast. I have heard from one N-trak modeler who often takes his N-trak modules to conventions and he reports that no one noticed (or at least no one commented) when he converted to code 55 from code 80. However, he gets lots of comments when he makes other changes to the details.

Still, I am using code 55 on my main layout, in large part because code 55 track products look a lot better overall, not just the rail height, than do the code 60, 70 and 80 N scale products.

For the record, the reason N scale track manufacturers initially chose code 80 was operations reliability. As with all model train scales, oversize rail and wheel flanges were chosen to minimize derailments. Today, modern plastic and metal manufacturing techniques are much more precise than they were in the past, so we can acheive even better operational reliability without the oversized rails and flanges. Even so, there are potential operational issues with certain brands of N scale code 55 track, and I'll cover that in a later post on track brands.

For those interested in more details on rail heights and sizes in the prototype and in the model scales, here is a good site.

For those interested in very high accuracy model railroading, what is commonly called "fine scale" modeling, the Proto 87 site is worth a visit. The term "Proto 87" simply means trying to precisely and accurately model the prototype in HO (1:87) scale. In addition to getting the rail size right, they also try to model exact replicas of (for example) switches and wheel flanges. This type of modeling is not for everyone, as there is a lot of extra effort required. But its a lot of fun to look at the results of a successful Proto87 modeler.

Atlas Code 80 Switch Prep Procedures

Atlas Code 80 track and switches have seemingly been around forever, literally since the 1970s or 1960s. They are still sold today because they have one huge advantage: price. An Atlas Code 80 #6 remote switch, which includes a snap relay switch machine and a switch control box, can be bought for $13.35 at Brooklyn Locomotive Works. By comparison, the combined cost of the more widely preferred Atlas code 55 #7 switch with Tortoise switch machine and a typical SPST switch box will run you at least $25 -- and other options such as Peco or MicroEngineering switches are significantly more expensive even than that.

Of course there are reasons Atlas code 80 is so cheap. First, it doesn't look anything like prototype track. Second, functionally speaking the slow-motion switch machines are superior to the old snap-relay variety. And third, there are valid concerns with the Atlas code 80 switches' out-of-the-box reliability.

I use Atlas code 80 in staging because: 1) prototype-like looks aren't important in staging, and 2) with 73 switches combined in my 5 staging areas the cost savings are significant. This means I had to come up with a solution to address the Atlas code 80 switch reliability problems, and that's the topic of this post.

Here is a picture of an Atlas code 80 #6 switch in package next to one that has been prepped for the layout. I've added three circles at places on the prepped switch to help with the explanation of the prep procedures. To get a bigger view simply click on the picture:


As far as I know the procedures here will also work for Atlas' smaller #4 switches. However, I recommend #6's because they are longer, with a wider curve radius, and thus more likely to operate reliability with any N scale equipment.

One point worth noting is that Atlas has improved these switches many times over the decades. Most of the chronic problems that were documented in the 1980s, for example, have been addressed in the current version. The issues that remain are addressed in the steps below:

1. Open the package. The switch controller and screws can be set aside until if/when you are ready to use them for switch control. The 6 rail joiners should be separated with a cutter, such as the Xuron rail cutter, and trimmed so that there is no excess metal on the ends of each joiner. I then put them in a rail joiner drawer until they are needed on the layout.


2. Inspect the switch. Look for track out of alignment and test the switch machine manually. Use a truck, such as a Micro-Trains replacement truck, to see if it catches anywhere when run over the switch. Once you've followed these procedures with several switches you'll probably be able to see the problems areas by eye without testing.


3. Look closely at the rails inside the red circle in the photo above. This is where the closing rails meet the point rails. I find it helpful to use a magnifying visor for this step. In almost all cases the closing rail is not in line with the point rail (the point rail is the one which moves), but instead sticks out a little. This "sticking out" can cause trucks to skip over the bump and in bad cases can lead to derailments. Using a small metal file gently file down the side and top of the closing rail end, and if necessary the end of the point rail as well, until the transition from one rail to the next is smooth. Note that this problem usually affects the diverging route but not the straight one, but just to be safe I file the rails for both routes.


4. Now inspect the plastic frog inside the yellow circle in the photo above. In some cases the frog is too big and thus can cause wheels to bump up when they travel along the frog. The solution is to file down the top of the frog tip, then file the sides of the frog tip to assure that wheels pass by smoothly all the time.


5. Check the ends of the point rails (shown inside the green circle in the photo). To be honest I've not seen a problem with these in the current generation of Atlas code 80 switches, but historically the point ends can be off level with the main rails. If so you'll need to add shims under the point rails or file down the rail tops as appropriate.


6. Now test the switch machine. This can be done by wiring it up per the instructions on the back of the switch package. However, to save time you can take two wires, one black and one of another color, and briefly touch them to the accessory terminals on your DC power pack. Then do the same with the other color wire and the black wire. Test only once, to avoid overheating the switch machine. Again, I've not experienced any out-of-the-box problems with this generation of Atlas code 80 switch machines, but if a problem does arise I want to find it before I install the switch on the layout


7. Finally, as the switch wires are short you'll probably need to extend them. I strip about 3/8" of insulation off each wire and crimp yellow butt splices (gauge 16-22, as shown in photo) that are found at Radio Shack. I don't add wire to the other side of the butt splice until the switch is on the layout, as until that time you won't know how much additional wire will be needed.

After that the switch is ready for the layout.

Thinking about switch control on main layout

So, the decision I made a couple of days ago to go with Tortoise switch machines on the main layout sparked my thinking about the whole switch control issue. This isn't a new issue at all, but sometimes you need a spark to help you finally reach a decision.

I researched the docs at Digitrax, skimmed various web sites, and started an email discussion with Mike Gleaton at Charleston Digital Trains, who is my primary source for DCC paraphenalia due to his extensive helpfulness and responsiveness, not to mention his ultra-competitive prices.
Long story short, the solution seems to be the Digitrax DS64. Yes, I knew the DS64 could provide digital control of 4 switch machines (either slow motion or snap relay), but at $48 + shipping I was hoping for something cheaper. But here's what I learned are its advantages:

1. Meets requirement: It can use a non-track power source. This is important because otherwise a large number of stationary decoders can drain the track power, requiring boosters and potentially interfering with train operations. A single PS12 power supply ($8) can power 20 DS64s, possibly more.


2. Meets requirement: There are slots for additional input devices, such as a fascia board with switch controls. This is huge -- I thought I'd have to buy separate DCC devices to support this feature.


3. Meets requirement: The DS64 supports 8 routes. Now, I've known this since I first read about the DS64, but I didn't really think about it until now. You really do want routes for things like ladder switching, because otherwise instead of clicking one logical switch for the track you want to go to, you have to click all the switches in between. The idea of one-click switching is helpful both for manual switching boards and for simplifying dispatching for a large layout.
   
   But if you have a lot of switches you'll need lots of routes. For example, a single 5-track yard with switch ladders at both ends will require 10 routes -- two (one for yard entrance, one for yard exit) routes for each of 5 tracks. The biggest Digitrax command station, the DSC100, which I have, supports only 32 routes. Each DS64 adds 8 routes, twice as many as the number of switches it supports, and since the routes can include switches attached to any DS64, a layout full of DS64s gives you more routes than you can realistically use, even if you use the "virtual" route addresses that Digitrax suggests for special switch situations.


4. Meets requirement: It has sensors to provide feedback to the command station, the computer, and the fascia switch board indicating the position of the switch.


5. Very useful: The DS64 can be configured to turn power off to the Tortoises 16 seconds after the switch movement is finished. This isn't true for all layout situations, but I have found that when the Tortoise is powered off on my layout it still holds the switch points firmly against the rails, thus making continual powering of the Tortoise unnecessary. I hear that this is not always the case, but perhaps my use of thicker-than-standard gauge wire for the Tortoise makes the difference.


6. Possibly useful: The DS64 can control both snap-relay and slow-motion switch machines, but not both types from one DS64. This gives me the option later of using the same technology, the DS64, when I start adding DCC control to my staging switches.


7. Possibly useful: There are also features related to signaling, which I haven't explored. But this is a topic I want to tackle before I get too much farther along.

So, I've sent Charleston Digital Trains an order for a DS64, a PS12, and a LocoBuffer-USB for computer control. Once they arrive I'll start experimenting.

Switch wiring milestone

Yeehaa! Ive finished all but one of that set of switches. I had to leave one undone due to running out of wire, but the one left is the easiest one to access. Even better, there were no more switch problems -- all the switch machines connected since the last post worked fine on the first try.

Here is what the temporary switch board looks like:


It's quick and dirty, but will suffice until I figure out a permanent solution. For each tier the switches are generally in a line, so I set up the board that way, with the left switch control being the "Straight" or "Normal" direction and right being the Diverging direction (as the label at the bottom indicates). The board itself was cut from a leftover piece of 3/4" plywood that had been used for paint testing, hence the interesting color.

The picture below shows the bridge area, sans bridge, with the switch wires visible. I bundled them together with tape but haven't fixed them in position yet pending the permanent switch control solution:


Except for the switch wiring everything is as it was a week ago. I did vacuum all around in preparation for finishing the bridge, which I will start today.

There are a couple lessons I've noted down from this week's experience:

1. Despite my intense budget consciousness, I've going to bow to the inevitable and accept that the best choice for switch power on the main layout will be the popular Tortoise. These are expensive relative to the snap-relay type of motor, but you can get them for $160 per 12 pack at Charleston Digital and the other price leaders, which reduces the pain somewhat. I reached this conclusion after working with the Atlas snap-relay switch machines. Yes, Peco and others make a better snap-relay than Atlas, but the whole concept just isn't as sound, in terms of reliable operation, as the slow-motion switch motor.
   
   Of course, once you accept that you have to use Tortoises for reliability there are a few other benefits that come with them. You get the SPST leads for powering the frog, you solve the problem of how to have the system remember the switch position, and you can use a cheaper decoder for switch control (such as the Digitrax DS44) than with the snap-relays.
   
   On the down side, the Tortoise eats up a lot of space under the layout, and that might be a problem under the upper deck. So, I'll keep looking for an alternative slow motion switch machine. However, the ones I've seen so far are more expensive than the Tortoise.
   
   As I get closer to working on the main layout I'll order some 12 packs of Tortoises and some decoders to go with them. I'll also revisit a past project: modifying the Tortoise so that it can power two switches at once. This cost-saving approach is useful in situations -- for example, a crossover -- where both switches will always change at the same time, so two switch motors aren't necessary.


2. The other big lesson from this week was the benefit of completing a part of the project end-to-end before moving on. In this case, I learned that I could have saved time by filing the switch rails and setting up the switch wiring before I installed each switch. But I didn't learn that until after I had the switches in place and found problems during testing.
   
   So, thinking ahead to how to apply this lesson on the main layout, I've decided to complete the scenic treatment on one section before I go back to laying new track. This is because I expect that once complete I'll learn some things that may change my track laying approach. The section I choose will probably be one that gets the least notice, so that mistakes won't be as obvious. Probably the north side of the peninsula, which not only can't be seen when you enter the room, but is also one of the least visually interesting segments of the layout.

I'm Me-e-e-l-l-ting

I think I've figured out the Atlas switch machine problem.

As mentioned in the last post, the electric coil in these things gets very hot very fast. Just 3-4 switches in quick succession is enough to make the outside of the plastic case hot to the touch. A few more and the plastic case will start melting inside. Once that happens the plastic pieces that move inside can get jammed causing the machine to fail.

And of course, your natural response to having the switch machine fail is to run the switch a few more times to see what's happening. That's what I did with Switch 4M (middle tier, #4), thus making the machine so hot that the case is now irrecoverably deformed due to melting.

The solution is to have pauses between each time you flip the switch -- ideally of 10- seconds or so. This is NOT a problem for normal operations, but of course it's something you have to tell kids to avoid.

I now have all 5 connected switch machines working nicely, including one replacement. I also now have a solid intuitive understanding of the internals of these, which will probably be helpful down the road sometime. As I connect the rest of the machines I'll be watching closing for the same symptoms -- and if there aren't any I'll consider this problem solved.

Unfortunately, this problem did slow layout progress. I did nothing on the layout on Wednesday or Thursday. Granted, this week was very intense at work, giving me little time for hobbies. However, if my current task had been something mindless like wiring up more track I probably would have done some of that just as a mental break from work. But with the task being the solving of a difficult problem I just avoided tackling it until Friday night.

Oh well, I'll try to get the rest of the machines deployed and the bridge completed this weekend.

Stuck with Atlas switch machines

It's been a busy work week, which has slowed progress somewhat. But the real culprit has been the problematic switch machines.

I have set up a board with 16 switch controls, wired and joined together. That's 116 screws and 10 sections of wire needing insulation removal and joining to terminal screws. Not that I'm counting. I've connected 5 switch controls. That's 45 wire ends requiring removal of insulation, 30 wire ends to be connected into butt splices, 15 wire ends connected to screw terminals, and 10 labels to affix. Not that I'm counting. Only 8 more switches to go until I can return to the bridge and the upper level.

Unfortunately, I've run into some problems along the way. Remember that all of the Atlas switch machines were tested prior to setting on the layout. I'll need to be more careful in my testing next time. 2 of the 5 that I've connected so far don't work correctly. In both cases they consistently switch in one direction but not the other. I've taken apart and tried to diagnose, but haven't solved the problem yet.

In the past I've set problems like this aside and moved on. Usually that's been a mistake. I really should understand the problem and have a good sense of the innerworkings of the machines before I move forward deploying 50+ more of these, because I may find that the best corrective action is something preventative that I can do before deployment.

One really frustrating thing is that these things get so hot so fast. The instructions are clear about never holding the button down for more than a second, and I never do. However, when testing anything I'll typically repeat the operation for several iterations to see how it behaves -- but if you do that with the Atlas switch machine you can literally melt the plastic encasement, as I found with the 4th switch machine I connected.

So, when I get back to the layout tomorrow my sole task will be to figure out what's wrong with these two faultly machines.

Bridge work interrupted

Before laying the bridge track all that I'd planned to do was to vaccuum up the area and hand-clean the lower tracks one more time before putting the bridge back in place. But, once I started to do that I realized there were two projects, one small and one large, that needed completion before I put the bridge in place semi-permanently.

The small project involved putting scotch tape around the wire labels, some of which are already showing signs of non-stickiness. These labels have already proven helpful in tracing wiring for one reason or another, and I don't want them to fall off a year or so from now, forcing me to hand trace the wires to see where they go.

The big project is to connect/automate the remote switch machines. My practice to date has been to switch manually, with the idea of adding remote switching later. However, the upper tier bridge will block hand access to most of the switches underneath, so we'll need to have remote control of those switches now.

I have a vague idea that I'd like all layout switches to be remote controlled from 3 places: a computer, a DCC throttle, and a front panel. This is to provide maximum flexibility of operations. Doing some research it appears this is going to be quite a challenge, for reasons I'll explain in a later post. And expensive. And it's going to take some time to think this through before I'm ready to test out a proposed solution for remote switching.

So, for now I'm going to set up a temporary switch board for the south end of staging -- the north end will be able to follow the manual switching practice as those switches will still be accessible. The temporary switch board solution will combine stuff I'll have to do anyway, such as extending the wires to the switch machines, with stuff that is temporary but doesn't require buying anything I don't already have, such as using the "push button" switch controls that come with the Atlas code 80 switches.

I started this project Sunday. All switch machines were tested before installation, so I didn't expect any problems. So, naturally, I ran into a problem with the first switch machine, then proceeded to destroy it by pulling too hard on the wire while trying to fix the problem. Argh. Oh well, replacement switch machines are cheap and I'll probably need to keep 4 in stock (2 for left switch, 2 for right) as normal practice anyway. For now, I've simply grabbed a replacement machine from another switch.

I'd like to complete this Monday, but there are 12 machines to strip wire, add connectors, run and staple wire, add labels, test, adjust, etc. Maybe I can get a kid to help out with this ....

Why we test

I completed the middle tier track laying & wiring in the area next to staging then, as usual, tested it out. While this part of the project went smoothly there was one problem I found during the test that will probably save me a lot of time later on.

Here is a picture of the layout as of this morning:


What the test uncovered is that some of the #6 code 80 Atlas switches have a tendency to catch the wheel of a car taking the diverging route. The catch is at the end of the diverging closure rail (the inside rail) right where it meets the hinged part of the point rail. This became obvious with the Kato SD90/43MAC, which is fast becoming one of my favorite engines for finding latent track problems. I suspect that the long 3-axle trucks make this engine more susceptible to this type of issue.

There was one switch where it was very noticable, but once I watched for it the others all demonstrated the same problem at least a little bit. At no point did any derailments occur, but this is the sort of bumpy ride that leads to intermittent derailments.

The solutions was simply to file that edge of the rail. I did this on all the switches that are in place, and will include that as part of my switch-preparation routine, adding maybe a minute per switch. I also found, on one switch only, that the plastic frog and the plastic rail that adjoined the closure rail were just a bit too tight in the diverging route, causing a bump. Again, a quick bit of filing down solved this, and I inspected all other switches for this problem.

Otherwise, the track laying and wiring process was uneventful. On a minor note I found that a staple used to hold a pair of wires in place went in too hard and cut the insulation on both wires, causing a short. Easy repair with electric tape and a new staple. But that staple was located in an awkward spot and I must have had the gun lean too hard into the wood. I will take care to avoid this from now on.

Next task: The 3rd tier bridge. I'm in the measuring and planning process now and have decided to make it removable, which adds complexity up front but is probably essential for long term maintenance of the track underneath.