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.

WiFi control! Digitrax LNWI & WiThrottle

Short summary:

1. Using WiFi for train control is new in the last 11 years, works great and is the way to go.
2. Digitrax LNWI module is inexpensive and provides a dedicated WiFi network for 4 devices (phones, tablets) to control trains and the layout.  It's actually very easy to install and run.
3. You can buy a WiFi throttle device, but easier is an app for your phone or tablet.  
4. Digitrax biggest weak point - the user interface - becomes a non-issue for layout running with a WiFi throttle.  Also makes moot the problems with Digitrax radio throttles.
5. Cons: WiFi interference possible, phones can't be on cell network when being used as throttles.  See main text for solutions.

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.

Power District 2

So, following up on the last post, it took 3 evenings of work to complete the rewiring for power district 2, not just 1 evening as I'd hoped.

Although I reused the feeder wires that were already in place everything else was installed from scratch: power bus, terminals, labels, soldered connections, and even two sets of new feeder wires. It was interesting and a bit nostalgic going over wiring that I'd installed nearly 4 years ago when I started on this layout. At the time, in my innocence, I'd used terminals that were 4-6 feet apart and as such had 22 gauge feeder wires that were commonly longer than three feet and occasionally as long as 6 feet. I've since learned that this just won't do -- the maximum lenght of thin feeder wire should be about 2', assuming you have a connection to each rail, and ideally less than that. Power District 2 now meets that ideal.

I'll need to post a map of the power districts at some point. Power Districts 2 and 3 overlap, both covering the lower peninsula and west wall, and slightly encroaching into the north wall. 2 includes the SAMR double tracked main, the interchange yard, the track that connects the SAMR to staging, and the one Union Station approach that is not an auto-reverse district. Power District 3 includes the BNSF double tracked main and the commuter train yard, plus the track that connects this line to staging.

As I've worked through this I've accepted that Power District 1, which covers all three tiers of lower staging, is way too large. I have added a project to my to-do list to convert the middle tier to it's own power district.

I've also had a good conversation with someone from the Digitrax user group who suggests that the PM42, which I'm using for AR, performs acceptably as a power district manager but not for AR. The problem is that it is too slow to react to shorts to be an effective AR. Now, I'm using N, while he is using HO, but I've seen similar comments before. I think that I'll order a PSXR to replace the PM42 on the AR function, but then reprogram the PM42 for 4 power districts. This will need to be done fairly soon as I hope to soon have more power districts on line.

So, what to do next? I still have the same goal stated in the last post, regarding fully automated switching functionality for the SAMR line by end of next weekend. I think I'll try to set up the DS64 circuit. This means establishing the standards for numbering of DS64s, and wiring them for power and Loconet, then setting up two of them (the second one is en route now). After that I'll have the power setup in place for me to test Tortoises as I install and tune them. If all goes well I'll have DS64s in place and two Tortoises working smoothly by end of the weekend.

Wiring Standards part 6: Power cabinet and Loconet

I created a number of posts last year about the wiring standards for the layout. This post extends on those by describing standards that have been developed and/or refined as a result of the power cabinet work last weekend.

Here is how the cabinet looks most of the time:


The goal was to have a clean appearance with everything easily accessible for operations and maintenance. Regular operations can be performed by opening the cabinet to start the layout and get the throttles -- at which point the doors can be closed again until operations are over. For maintenance the cabinet can be pulled away from the layout, since it is on rollers, to access the wiring in back of the cabinet or underneath the layout.

Here is the view with the doors open (in this view the cabinet is pulled away from the layout):



The top shelf is currently for storage of throttles and of Digitrax manuals. I've earmarked key pages that get frequent use, like CV tables, how to program consists, Ops mode programming steps, etc. As the number of throttles grows I'll likely need to have a separate place to store them.

The second shelf has the DCS100 command station on the left and the power strip on the right. The power strip is screwed lightly into place and all the power supplies needed for the layout are plugged in place. If you click on the photo for the larger view you'll see they are also all labeled with their purpose. In this setup, under normal operations the starting and stopping of the layout is done with just the main switch on this power strip.

The DSC100 has various wires attached to it but I've tried to keep those organized too. The power and ground outputs, red, black, and green, go directly from the DCS100 to the barrier strip on the left wall. Any device that needs connection to the DCS100 is connected to the barrier strip, not to the DSC100 directly. All power wire is 14 gauge, and as with the rest of the layout pairs are twisted together and labeled.

The DCS100 also has a programming track set up in front of it. This allows for quick decoder programming during an operating session if for some reason Ops programming won't work. It can also be used at other times, but for normal locomotive work I'll probably use the Digitrax Zephyr at my work desk.

The empty space on the second shelf is reserved for a booster, which may be needed when I start building the upper deck of the layout, or for a second power strip.

The third shelf is for power management, as can be seen from the labels in the larger picture. On the left is the PSX4, which provides power to districts 1, 2, 3 and the auto reverse (AR) sections that are controlled by the PM42 (the middle device). These are lightly held in place and have padding protecting them from the shelf itself. The empty space on the right is reserved for the second PSX4 for the upper deck districts. As I plan to have 8 power districts plus a district for the PM42 I will also need a PSX1. I plan to place that in front of the PM42 and wire it to the PM42.

During operations if we get a circuit break or if we otherwise have to view the power management LEDs for problem diagnosis we simply open the cabinet to see them.

The bottom shelf is currently occupied only by the main power supply for the DCS100. (It's a DCC Specialties device, recommended by Mike Gleaton.) The rest of the space is reserved for an additional power supply for a booster, if it turns out that is needed, and for transformers for the lights and switches.

Here is a look behind the cabinet:


This does look a bit messy with all that wire, however if you look closely you'll see I've tried to tame the mess a bit by setting up hooks around the back of the cabinet for routing the wires. Plus, the wires are all organized into labeled, twisted pairs. However, because the cabinet must be allowed to roll away from under the layout there has to be some slack in the wires that connect the cabinet to the layout. All these wires can be disconnected, if need be, by plug or by undoing the electrical pigtails, and all are labeled to allow easy reconnection. However, the slack wires do make it look messy. The wires for power districts 3 and 4 and for the upper deck AR section have already been deployed, so that attaching these later will be a simple matter of connecting them to the wire ends at the back of the cabinet, instead of having to add wires inside the cabinet.

One other minor wiring standard emerged from this work, and that had to do with the Digitrax UP5, UR91 and UR92 front panels. These are distributed throughout the layout on front fascias to allow plugging in of Digitrax throttles anywhere. UR92 is the two way radio receiver panel, the two UR91s are one-way radio receiver panels, and the UP5s are basic panels.

These panels have two wired connections. One is Loconet, a 6-pin cable. The other is a single 18 gauge power wire. The single wire, together with the loconet ground wire, allows up to 10 panels to share a single power supply. The UR92 doesn't have the power wire because it requires a dedicated power supply. The power supply for the 10 other panels is connected to the UP5 nearest the power cabinet.

One standard I'm following is to configure the loconet in a branching configuration, avoiding loops, per the Digitrax recommendation. The other is to label the power wire "UP5" every few feet to distinguish it from other wires. The Loconet cable is not labeled, as it is clearly unique.

The last point is placement of the panels. Usage-wise, radio throttles can connect to any panel, not just the radio ones. The one-way throttles use any panel to plug-in to select or dispatch locomotives, but once that is done the throttle is disconnected and communication is automatically done via a one-way receiver. For this reason the two UR91s panel/receivers are placed in the two different rooms, and roughly in the middle of the rooms. The two-way throttles don't need to plug in at all unless they get confused, however they do need to be initialized when they start up by plugging into the UR92 for two seconds. For this reason the UR92 is placed on the right side of the cabinet, so that you can plug in at the same place that the throttle is stored. That also is roughly the center of the layout, which should minimize any chance of radio interference. You can see the UR92 panel in the upper right of the first photo with this post.

And when the Trains come marching in ...

The title is a punny reference to the latest Super Bowl winners. It was a fun game. I was making progress on the layout at the start but by mid-3rd quarter I just focused on the game.

Regarding the weekly task list from last Thursday we got most of the targeted stuff done, plus a few things not on the list. #1, the switch machine issue, is resolved temporarily in that the crossover switches do work automatically with only one Tortoise and the derailments have stopped. The solution didn't take long -- it was the same concept I was trying in 2007 but this time with better materials. However, it's now only a proof of concept -- when I start the project to automate all the switches I'll re-do this solution in a more solid manner.

#2 is done, as I noted on Saturday, except that I need to finished writing up my post on the power cabinet. #3 is done except that I need to start the weekly routine of using the CMX car. The only major goal I didn't complete was that I didn't get started planning #4.

In addition to the planned tasks 3 other things were done. I resolved #5, as I reported earlier. My son successfully did his first decoder install on his own, a DN163K2 "plug and play" Digitrax decoder into a Kato SD90/43MAC. Worked on the first try. The only minor glitch here was my fault -- the locomotive number on the shell is 118, but when I assigned that as the DCC address it wouldn't run. Eventually I worked out that 118 is considered a 2-digit address in the Digitrax system (the cutover to 4-digit addresses starts at 128), and knowing that we were able to get it running immediately.

The other bit of work this weekend came as a result of a problem we ran into on Sunday. One really nice thing this weekend was that Daniel and Emma joined in a mini-operating session with me which lasted about 2 hours, only ending when I said it was bed time. Emma did well figuring out the DT400R throttle and is getting pretty good at making sure the switches are set correctly. On Sunday she asked to start again, but after a while a short occurred.

As I investigated the short I found that the PSX showed both Power District (PD) 1 and 2 as shorting, which seemed wrong. We stopped playing, but when I got back to the layout later I started a mini-project to investigate whole layout wiring.

As it turned out the short was caused by an engine going over a switch that was set incorrectly, something I didn't think about because we don't use that switch right now. But, it was a useful exercise. I found that PD1 and PD2 were not fully isolated, because when I cut the gap in the Peco code 55 rail I didn't cut deep enough into the ties. I also learned, to my surprise, that when the layout has no power one of the rails (the "left" or "black wire" rail) is still connected electrically across the PDs and the ARs, but the other rail is isolated. This must be the standard way circuit-breaker devices like the PM42 and PSX operate, but I didn't expect it and as a result I was confused for a while about the problem symptoms.

One other point I've been aware of for a while is that in PD-1 the rails are not completed isolated, but instead register something like 100 ohms of resistance between them. Not enough to prevent operation, but it bugs me. I'm adding this to my problem log to work on again.

Another problem added to the log is to investigate why the D402D (new two-way radio throttle) loses connectivity from time to time. My first step will be to actually read the manual.

Finally, as a result of this investigation I also ended up fixing some of the track around the electrical gaps.

So what tasks to work on this week? Here is the new list:

1. Track cleaning.
   
   Get the CMX car running over all track on a weekly basis.
   


2. Track scenery.
   
   This is the item noted in last week's list. This is a potentially big project, with goal of being able to make the Peco code 55 look like realistic, modern, concrete-tied track.
   


3. DS64 deployment.
   
   Also noted last week. This project is to figure out how to get the stationary decoders working with the switch machines.
   


4. Extending middle tier staging.
   
   First step is size and order the needed Atlas code 80 track. Once it arrives the project will be to build the track from the middle tier staging to where the hidden track meets the sceniced main line track.
   

My goal for the end of this coming weekend is to have a happy solution for item #2. This is a big task that will require a lot of thinking and trial-and-error, and my experience is that I get more done if I also have some smaller tasks as part of the same timeframe goal. So I'll also target item #1, ordering the track for #4, and to resolve 3 of the items on the problem log. I don't think I'll start the DS64 until I have an answer for #2.

Upper AR problem solved (?)

I was testing the Upper Auto-Reverse problem mentioned in the last post when it suddenly went away. I determined that the problem was that only one rail was switching polarity, not the other. Trying to isolate the cause I used the multi-tester on the PM42 connectors, but having forgotten I turned the MT off, touching the connectors caused the DCS100 to short circuit and the PM42 to switch polarity again (at least the indicator light changed). That reset apparently stopped the problem, as the PM42 now works fine again.

I'm putting this into the "monitor" category on the problem log as I don't understand the solution and thus the problem may reoccur. I'm also wondering if this was the same problem I had with that one "bad" PM42 section in 2007. Hmmm....

DCC order

As I noted earlier, I had an email conversation Thursday with Mike Gleaton at Charleston Digital Trains and got some good advice on the power management module.
I then sent in the following order:

1. PSX4 Power District Circuit Breaker. This the the power management module I decided on. Mike suggested that I probably could get by with the cheaper Digitrax PM42, since N scale with its lower voltage and amperage generally won't run into the same problems HOers commonly report with the PM42. But given my less than positive experience with the PM42 I opted for the upgrade.
   
2. UR92 Duplex Radio Tranceiver. Last year Digitrax released the long-rumored two-way radio communication system. Previously the one-way system meant that you had to plug in the radio throttle to change locomotives. The UR92 is the radio base station for the two way. I'll still keep my two one-way UR91s for any one-way throttles I or my visitors may have.
   
3. DT402D Duplex Super Radio Throttle. This is the latest and greatest Digitrax throttle, with upgraded functions relative to the DT400R *and* two-way radio communication. As I had only one DT400R I've been wanting to get a second one "someday", and now that my son, father, and I are actually running trains the need for an extra throttle has become apparent. One other nice thing is that Digitrax can upgrade my DT400R to a DT402D (as noted at the bottom of the linked page), which is something I'll do after I receive my new DT402D and get it running.
   
4. DN163K2 N Scale Mobile Decoder. This was something I included "as long as I am making an order anyway". I have a Kato SD90/43MAC I got last year which needs a decoder, so this will be it.

Meanwhile, progress continues on my remaining tasks for the week. All the bad track areas are now fixed, I bought the extra shelves for the power cabinet (just have to trim them to fit and install them), leaving me only with the rewiring under layout in the area above the power cabinet. My son and I are also fixing up some cars with minor repair issues that I've been ignoring. So we should have everything on the target list done by Sunday, and even some things not on the list.

Short solved -- and more

I previously mentioned that there was an electrical short somewhere that affected the middle and lower tiers. I'd spent probably an hour or so trying to find it with no luck, so I stopped looking on March 28th and focused on the upper tier.

Today, with the middle tier ready for new track, I started the search afresh and found it within a few minutes. The guilty bugger was the staple on the left shown in this picture:


As often is the case, when you set a problem aside then revisit it later you find a new approach that works. In this case I realized that, having looked at everything 3 or 4 times, the problem almost had to be a staple that penetrated the insulation on both wires. Then I realized I could find it easily by using the multi-meter and checking for resistance between each staple and the track. Sure enough, this one registered loud and clear on the meter, and the repair took a minute.

Once that was done I started putting down new track. This picture shows the glue drying on two new track sections:


A close look on the left side of the picture reveals that there is a second layer of the blue roadbed on top of the first. As I noted in my last construction post, the new plywood I'm using is about 1/8" thinner than the old, and this caused the transition from one to the other to be uneven, even after I shimmed it. The second layer of roadbed seems like it causes no problems, however in order to keep the track as smooth as possible I'm letting this dry in place, without weights on it. This is an experiment -- if it works I might use the same technique for the rest of the staging track.

Next up: lots more track installation on the middle tier.

Electrical short debugging

As mentioned earlier today, I discovered an electrical short when testing the newly laid upper tier track. At the time I'd inspected the new track and feeders and didn't find the cause.

This evening I tried again. First I finally cut the rail between the upper tier Auto Reverse (AR) section and the main track. Once done I confirmed that the problem was with the main power district, not any of the three AR sections. Then I very closely inspected all the new track and feeders, including switches, and even moved wires around as a precaution, but still did not find the short.

At that point I began to suspect the track laid earlier for the lower and middle tier. I'd successfully tested that track at the time, but haven't run trains on it for over a month, so there is a decent chance that some of the adjacent construction activities could have caused a short. I cut the power bus wire between the I and J terminals in a way that will allow for easy reconnection. Then I tested and confirmed that the problem is with the older track.

At that point I tested the new track with the SD90/43MAC and everything worked great. The good news here is that all the precautions and applied lessons seem to be resulting in better trackwork, especially the switches.

The bad news is that I still have an electrical short on the old track. I inspected everywhere i could reach and removed several staples to look underneath but found nothing. I'll probably need to remove the upper tier bridge, and in order to do that I'll need to finish the rail cutting for the left side of the bridge.

Hopefully I can resolve tomorrow. If not I can continue work on the upper and middle tiers for at least a while before this electrical short blocks progress.

Wired .... but ...

20 pairs of feeder wire and 5 sets of switch machine wire, including the unwired one from the middle tier, have been completed, and the new track has been cleaned:


Alas, testing this morning found an electrical short somewhere in this picture. I've searched for the obvious causes with the newly installed wire, such as feeder wires reversed or broken wire insulation, and found nothing.

In the back of my mind I knew I should have been testing for shorts with the multi-meter as I made each wiring change -- but I didn't. Lesson learned. I will do so from now on.

When tracking down shorts the first step is to isolate parts of the circuit to narrow down the possible causes. Unfortunately, this is one big circuit except for the AR sections. (Hence the rational for power districts.) This may take some time to locate.

Wiring standards part 2: Amendment

One minor addition to the Wiring standards part 2: Terminals and Feeders post: The terminals will always have the black wire connections on left side, red on right side.

Why? Just because.

Visio wiring diagrams

So the past few days have been very busy both with work and with a home project. I have kept up with my promise to "do a little bit each day on the layout", but unfortunately this week the stress is on the word "little". I did make a tiny bit of progress on building more staging subroadbed, and have spent an hour or two with the nice package of DS64, Tortoises, and the LocoBuffer that arrived mid week. I'm starting to practice with these components so that I can understand their innerworkings, and when I do I'll post on that topic.

The other bit of progress was starting work on the staging Visio diagrams. Here are a couple of screenshots that show how these will look. First, this is the diagram of the lower tier of staging, near the loop:


Here is the "Key" section of the diagram, showing what the various symbols mean:


Hopefully this is self-explanatory to those who have read the wiring standards posts. It may also help to go back to a picture of this section of layout, before the bridges were put in, to see the track in situ and compare it to this diagram.

The purpose of the Visio is to help with maintenance and changes later on. Yes, the wiring follows standards and labeling conventions, but the Visio shows how it all hangs together. If you've ever tried to sort out complex wiring that you built months or years before without a diagram or labels, you'll understand how helpful such a diagram can be.

The Visio does take some time to set up, but once in place adding new track to the diagram isn't that time consuming. I find it best to write down the track data on a notepad when I'm working on the layout. Later, when I have access to a PC but not the layout, I can still "work" on the layout by transferring the notepad data to Visio.

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.

Wiring Standards Part 5: Staging Switch Wiring

Staging uses Atlas code 80 switch machines, which have 3 output wires (red, green, black) of a very small gauge (28? possibly smaller?). The very small gauge is fine given that the machine is designed to accept only a short burst of current when the switch is thrown, and otherwise have no current running.

The wires that come attached to the switch machine are about 12" in length, so require extensions since the distance from switch-to-control panel is at least 3' and usually longer. For the wire extension I am using a "Rainbow" cable from Radio Shack, which is a ribbon of 4 solid 24 gauge wires in colors white, red, black and green. Connections from the ribbon to the switch machine wires are via clear 22-26 gauge butt connectors, also from Radio Shack, with the white wire left in place unused. The butt connectors are reasonably cheap ($2 for a pack of 24, which covers 8 switches) but the rainbow wire is $8 for a 20' roll, so I've got my eye out for alternatives.

Wires are labeled as other wires, with a labeling scheme of number-location, such as "4M" = 4th switch on the Middle tier. Numbering is generally sequential but that is not guaranteed. The wire number is currently the same as the switch number that will be used in operations schematics, but I reserve the possibility of changing the switch number for operations improvements without changing the wire number. Current locations are L (Lower tier), M, and U (Upper tier). The number-alpha format is designed so that switch machine wire labels don't get confused with the alpha-number format of track wires. However such confusion is unlikely anyway given that rainbow strips of wire are visibly very different than the red-and-black twisted pairs for track wire.

Switch wires are run under the subroadbed and bundled together with plastic cable ties to keep them tidy and reduce the possibility of pulling a switch wire out by mistake while reaching for something else.

Switch wires are run to the temporary control panel made up of Atlas switch controls. When the permanent switch control solution is designed some of this wiring may need revision, but at this point I think all that will be required is to disconnect the wires from the Atlas switch controls and connect them to the permanent device.

Wiring standards part 4: Auto Reverse and gapping

I was going to start this post with a description of Auto Reverse (AR) sections -- what they are and how they work. Then it occurred to me that someone else probably already had done that and, sure enough, you can find such a description at Wiring for DCC.

My layout will have 6 standard AR sections, 5 for the return track in each of the staging areas, and one for the wye at Union Station. There will also be one crossing with live frogs on the upper deck, and that requires a special application of an AR device. I'll address that topic in a later post, probably not until upper deck construction is underway.

Before getting to the wiring standards, there are a couple of AR section design standards to mention. First, all of the 6 standard AR sections will consist only of a single track, no switches or crossings. This not only simplifies installation, it also greatly reduces the possibility of accidentally triggering the AR device through electrical shorts (more on that later in this post). Second, standard AR sections will be at least one train length long -- some possibly fitting two or even three shorter trains in a pinch. In general you want AR sections to be at least as long as your longest train. This is pretty obvious if you think of every car as potentially carrying electrical current in the wheels. It's true most freight cars have plastic wheels, but many have metal wheels, and all it takes is one wheel to bridge an insulating gap and cause a short.

The AR wiring standards will be:

1. Each standard AR section gets its own power bus. Terminals won't be needed, instead feeders will be connected directly to the bus.


2. AR devices will reside in the power cabinet, making them easy to track with the other power devices and easy to debug problems.


3. The AR bus wires will be colored blue and yellow to distinguish them from the other layout wires. It doesn't matter which rail gets which color, so by convention I make the rail that is closest to the nearest wall for most of the AR section yellow. No reason, just because.


4. The wire for each AR bus is 16 gauge stranded. 14 gauge would be overkill because a) the length of the AR buses top out at 20' and b) the amperage draw will be much smaller than for the power district buses. 16 gauge stranded wire is available reasonably cheaply at Home Depot in multiple colors. The blue/yellow bus wires will be twisted to keep them together. They are labeled with "AR" and the name of each section, such as "AR-Upper Tier".


5. AR feeder wires are 22 gauge like the other feeder wires, are black, and like the other feeders are soldered to every other rail joint. Each feeder is directly connected to the appropriate AR bus wire. This is done by stripping a 1/2" off the bus wire insulation and the end of the feeder wire insulation, wrapping the exposed feeder wire around the bus wire, soldering, covering with electrical tape and then scotch tape, as electrical tape doesn't stick well. The electrical tape isn't really needed except that it might prevent oddball shorts in strange situations.

The photo below shows part of an AR section with the associated wiring:



The track nearest the camera is the return track for the lower tier. Below the track you can see the twisted blue/yellow AR bus wires, and at the left you can see an attached label with the name "AR - Lower Tier". On the right you can see two black feeder wires connecting the rails to the bus. You'll note that there is electrical tape around the connections, and scotch tape on top of that.

Part of the AR wiring standards remain undecided. First, I'm not sure what AR device I'll use. I have one Digitrax AR-1 on the layout now, which provides a simple AR function for one AR section, and it works like a champ. There are a few complaints about this on the internet forums, but mine has worked perfectly out of the box without need for adjustment. It may be that most of those who have trouble are using larger scales, or older locomotives. N scale may help in that I'm using lower voltage (the Digitrax DCS100 command station has an N scale setting) than HO, or that N scale locomotives draw less current.

On the other hand, I might have just been lucky with my one AR-1. But, I am currently leaning toward sticking with the AR-1 until/unless troubles arise. However, I hear good things about DCC Specialties' PSX, which replaced the similar Tony's Trains products, so they may be worth the small extra outlay in costs.

One product I recommend *not* using for auto reversing is Digitrax' PM42. I bought this because it was advertised as a low cost way to have 4 AR sections. That is technically true -- if you have a separate 12-18V AC power supply lying around doing nothing. And if you have a DT300 or DT400 command throttle to program it. And on top of that you'll need to do a nest of soldered wiring for the inputs and outputs. But the final kicker was that after I'd spent a couple of hours soldering everything and getting it all in place I found out that one of the 4 sections was faulty. ARGH. Yes, Digitrax support is excellent and they would quickly replace it, but that would have meant unsoldering everything, filing a support ticket, printing it out, and going to the post office to mail it. I've decided to accept the bad section and let the other 3 get used for power management.

The other pending decision is whether to connect the AR sections directly to the power booster or route it though a power district, and if so which one (maybe put all ARs in one power district). Logically you'd probably want ARs under a power district so that they don't short the whole layout. Except that there are frequent discussions on the forums about conflicts between an AR device and a PM circuit breaker. Fortunately, as all these devices will be in the same cabinet I can defer the decision, and once made it can be changed easily.

Finally, AR sections, like power districts and "live" switch frogs, require insulated gaps. You can either cut a gap in a rail and optionally fill it in or you can use an insulated rail joiner. I prefer the latter, and as a standard use the Peco insulated joiner even for Atlas track. It's smaller, hence less obtrusive, but it does a much better job of holding the rail in place. It can be disguised well as part of track scenicing. A situation may come up where the rail joiner is not practical, such as where the joint is on a tight curve, but until then insulated joiners are the standard.

Wiring standards part 3: feeder wires and track

In the last wiring post I covered the power bus terminals and feeders leading from the terminals. Now I'll cover the standards for connecting feeders to the track.

The first question is: how many feeder wires do you need per length of track? When you buy a starter train set with an oval of track you get one pair of feeders for the whole oval. But if you try to do that with a larger layout you'll probably run into trouble for two reasons:

1. Voltage drop, as mentioned before. The resistance of nickle silver rail is much greater than that of copper wire, so over a short distance of rail the voltage will drop enough to slow your trains.
2. Rail joiner problems. Rail joiners are designed to hold two rails in place and to pass electricity between the rails. However, over time some joiners will loosen or get dirty and eventually provide an imperfect connection. This will lead to even greater resistance (see point 1) or loss of connectivity altogether.

Now, this doesn't mean that every layout without power buses experiences rail joiner problems or large voltage drops. There are real life examples of layouts with long stretches of track where power is passed only by rail joiner and things seem to work well. However, in my experience every layout that relies on rail joiners for electrical connections has evenually experienced power drops. And this is why the power bus method is so widely recommended.

So, you may ask, we need to add feeders to the rails every few feet, but exactly how many feet apart? This is a matter of frequent debate on the model railroading internet forums. At one extreme are those who argue that rail joiners can never be trusted and thus each rail must get its own feeder. Not quite as extreme are those who argue feeders should be 3' apart, but don't require a feeder per rail in instances (like switch ladders) where many separate rails are used in a 3' span. At the other extreme are those who argue that spans of 10' or more are okay between feeders.

After reading what everyone said and thinking about my own experiences I tend to agree with those who don't see rail joiners as a long-term solution to connectivity, but I also don't see it necessary to space feeders every 3'. So, I decided to connect the feeders at every other rail joint. That is, feeders are attached at the rail joint, so every rail has a feeder, but there is only one feeder per two rails. This saves time and resources.

Alas, no solution is without controversy. By soldering the wire to the rail joint I am also soldering the rail joints, which is another big debate topic on the forums. Some argue that joint soldering causes problems because the metal rails will expand and contract with temperature changes. Soldering inhibits expansion, thus on hot days the rails will eventually bend out of gauge somewhere as a result. Others respond that they've never had this problem despite soldering their rail joints, and I'm in that camp. I solder all curved flex track joints and half of the straight ones, and in 2.5 years I've had no problems. I suspect there are as many as three reasons I've been so lucky:

1. The temperature variation in my room is not extreme -- from 60F to 85F at the limits. Even on our hottest days the room doesn't exceed 85F, and if it ever does there is a room A/C that is available, albeit almost never used. I suspect people who see problems often see greater temperature swings.
2. This is a very dry area, without great swings in humidity. Humidity doesn't affect the metal rails, but it can affect the roadbed and subroadbed depending on the material used. I have heard from many sources that Homasote -- a popular roadbed especially amongst those who hand-lay track -- is especially susceptible to contraction/expansion with humidity changes. It may be that the expansion/contraction problems some people are seeing have more to do with the roadbed than the track.
3. N scale may be less susceptible than HO and larger scales. I'm not married to this idea, as the rail sizes between the two gauges aren't that far apart (my code 80 in staging is not that different than code 83, which is the most common for large HO layouts). On the other hand, the track width for N is just over half of HO, and that might make a difference. However, for whatever reason I've noticed that it's rare for an N-scaler on an internet forum to complain about soldered joints causing track bendage due to expansion.

So, to make a short story long, I connect feeders to every other rail joint. Here's an example from the current staging construction:


As I keep mentioning, in staging looks don't matter. In fact, I personally like to have all the behind-the-scenes construction and wiring details visually evident in staging because visitors often find that stuff just as interesting as they find the sceniced portion of the layout. So, in staging I solder the feeder wires to the outside of the rail joint, thus avoiding potential problems with the wheel flanges hitting the wire on the inside of the rail. I'll describe the detailed procedures for soldering wire to rail, both for staging and the main layout, in more detail in a future post.

So, this post concludes the standards used on this layout to get power to the track under most circumstances. There are, however, a couple of exceptions yet to discuss. One is auto-reverse sections, and the other is track wiring for switches with "live" frogs. My next wiring post will cover auto reverse. I'll hold off on the discussion of switches with "live" frogs until I get back to construction on the main layout, as this doesn't apply to the Atlas code 80 switches used in staging.

Wiring standards part 2: Terminals and Feeders

The first wiring post covered power cabinets, power districts, and power buses. Now that we've got power to the underside of the layout in the form of the bus, we now need to get it from the bus to the track. The wires that connect the track to the bus are called feeder wires or just feeders.

Later in this post I'll discuss the standards I use for attaching feeder wires to the track, but the first question I want to address is how to attach the feeders to the power bus. There are two basic approaches:

1. Directly connect each feeder wire to the bus wire of the same color (i.e. same polarity). This makes sense for layout areas where track is sparce, such as a single track main line on a shelf. In such cases there aren't a lot of feeder wires so a short, direct feeder connection is best.



2. Connect all local feeder wires to a terminal that is attached to the power bus. This makes sense where track density is high. The staging area on this layout is an example of just about as much track as you can squeeze into a given area. In this case you simplify the wiring by connecting feeders to several central terminals.

There are other published wiring methods, but these appear to be the most commonly used. On this layout I use the terminal method predominantly, and the direct connect method in places where track is sparce.

An example of a terminal used on this layout is shown in the photo below. This picture illustrates the various wiring standards in practice:



There are many things to note in this photo. First, the terminal strip itself is an 8-slot barrier strip that I buy at Radio Shack for about $3 each -- cheaper than I've seen elsewhere. I don't say this is the best choice for this application, but it's the best I've found available and the price is good.

Second, note the power bus. This is the pair of 14 gauge wires near the top of the photo, one red and one black, that each weave through 4 of the slots on the terminal strip. It's a bit of work to strip that much 14 gauge wire and snake it through 4 terminals, which is the one drawback of this method. If you use this method be sure to use solid, not stranded wire for the power bus as it's much harder to do the same thing with stranded wire.

Note also that on the left of the terminal strip you'll see a label on the power bus wires -- "PD-1". This means "power district 1", per the standards discussed in the first wiring post.

Third, under the terminal you can see a label "1-J". This means power district 1, terminal J. By convention, terminals on a power district are named A, B, C, etc., with A being closest to the power source, B next closest, and so on. This convention is not a guarantee, as future layout revisions may result in, for example, a new terminal "P" inserted between terminals "C" and "D".
Fourth, you'll see smaller red and black wires connected to the wiring screws on the bottom side of the terminal. These are feeder wires. In general the feeder wires are on the side of the terminal that is most accessible given the location of the terminal.

Feeder wire conventions are as follows:

1. Wire is 22 gauge, red for attaching to the red power bus, black for black. 22 gauge is large enough to carry the power the short distance to the track, and small enough to easily work with when attaching to a rail. I prefer solid wire but I use stranded when solid is not available. I avoid buying "hobby" wire because it is incredibly expensive, instead buying the large spools from Radio Shack. Unfortunately you can't specify color when you order, and it is important to have an equal amount of each color, so instead of ordering in advance I just pick up a few extra spools when they have some in stock.


2. Feeder wire pairs are twisted in order to keep them together for easy tracking (feeder wire distances are so short that you don't have to worry about impedance).


3. The twisted pairs are stapled to the layout wood to hold them in place with a T20 (narrow) or T50 (wide) stapler, depending on the specific situation. I am careful to use long staples (1/2" or more) to avoid the staple damaging the wire itself.
   
4. Each wire pair has a name. For example, 1-J-3 means power district 1, terminal J, wire pair #3. The track location to which a feeder wire pair is attached is noted on a Visio diagram along with the name of the wire pair. (I'll post a sample of the Visio diagrams sometime in the future.)


5. Wire pairs are labeled with their name, usually dropping the power district as that is obvious by the location of the wire. So a typical label might be "J3". There should be at least two labels per wire -- one near the terminal and one near the track.


6. By convention, feeder wires are attached to one of the 4 terminal screws for their wire color according to the following pattern: From left to right, wire 1 goes to the leftmost screw, wire 2 to the next, 3, 4, then wire 5 back to the left most and so on.


7. I try to keep to a limit of 12 feeder pairs per terminal, which equals 3 feeder wires per terminal screw. If more are needed then another terminal should be added. This means that the screws, from left to right, would have the following wire numbers: 1-5-9; 2-6-10; 3-7-11; 4-8-12.

The next wiring post will discuss attaching feeders to track.

Wiring standards part 1: Power

I've built (or more accurately, partially built) 5 previous indoor layouts, 3 in HO and 2 in N scale. I learned a lot from each one, but they were all small, varying in size between 32 and 44 square feet. On this layout I've found that there are some things you won't learn until you build that big layout, and one of them is how to set up a well-organized wiring system. As I've reached the point in the staging reconstruction where wireing is added, now is a good time to start describing the system. This topic will take a few posts.

When I started this layout I took my first shot at a wiring system, and a lot of things did go well. I set standards for the type of wire used for each purpose, developed a system of a track power bus with terminals and feeder wires, labeled each wire per a naming system, and diagramed it all in Visio. I consider it a good first effort, but as I'm redoing staging this is a good time to revise the system with the lessons learned.

Some of the changes being made are due to things I learned in the process of doing, and some due to things I read in books or on-line forums that caught my attention now that I'm actually wiring a sizable layout.

Note that this is *my* system, not a general purpose one. There are all kinds of details that were chosen to match my layout's specifics, such as it being N scale or the use of Digitrax DCC. At a later date I'll probably post on how/why I made those decisions, but for now those are just the givens that influenced the wiring design.

Power Cabinet

It all starts here. You want to have a cabinet that contains your power supply, your DCC command station, booster(s) (if needed), and any electronic equipment that can be kept centralized, like the power district units, in one location. This is partly for ease in problem debugging. It also helps to have it all in one enclosed cabinet to keep out dust, etc. The other point is that you want to minimize the wire length of the power bus from your power station to the most distant track. (I'll explain why shortly.) So it 's a good idea to put the power cabinet in a central place to keep the longest power bus length to a minimum. On my layout I'll put the cabinet under the lower deck, on the west wall just north of the stair case.

(Aside: What do the terms DCC and DC mean? Think of them as digital (DCC) and analog (DC). DC is the way model trains are traditionally powered, that is by a transformer that sends Direct Current (DC) to the rails and the locomotive speed is determined by the amount of power received. DCC is Digital Command Control. For DCC the system provides AC (Alternating Current) to the rails in a constant high voltage, and uses the rails as a digital bus to send electronic signals. Each locomotive is equipped with a decoder to interpret the signals, and each locomotive is assigned an electronic address. In this way the decoder is told by the DCC command station how much power to route to the electric motor, or how to operate lights, or what sounds to emit, etc. DCC is more expensive when you consider the cost of just running trains, but it has enormous benefits in terms of simplifying wiring and operations and the use of features like sound and lights, as well as the obvious benefit of running multiple trains without any extra effort. The large majority of sizable layouts use DCC these days. I'll post more about DCC and DC sometime in the future.)

Power Districts

If you spend any time on model railroading forums that include DCC as a topic you'll hear old timers advise you to set up power districts. This is not a lot of work, and in a room sized layout it makes sense.

A power district is not the same as the "power block" concept from DC cab control, although in both cases what you are doing is taking a section of track and electrically isolating it from the rest of the layout. However, a power district covers a very large area -- on a DC layout you might have a power district comprised of many power blocks. The power district idea is this: it's common for an electrical short to occur on your railroad, most typically when a locomotive derails and a metal connection is made across both rails. When a short occurs your DCC command station will sense it and shut down power before anything burns out, and with Digitrax an audible series of beeps is emitted. At that point everthing stops until you find the source of the short. In a large layout such a search can take a long time, meanwhile everyone stops and waits.

The solution is to divide the layout into electrically isolated power districts, each with its own short-sensing circuit breaker. The size of the district is up to your personal tastes. For me I'll probably have 8 districts, 4 per deck, with the south staging room being one district on each deck.

(If you are running scales larger than N you may find, depending on locomotive density, that you need multiple power boosters. Each power district can receive power from only one booster, so you power district size may be constrained by your booster setup. This is, in practice, a non-factor in N since our locomotives don't require much power..)

You can set up your track at installation time with the insulators or rail gaps in place to provide for power districts, but not actually add the circuit breakers until later.

The power district management components will be resident in my power cabinet. Digitrax provides a PM42 for this purpose, but it does not get good reviews on the internet Digitrax forums. I have one PM42 and I have to say I understand the complaints -- it's requires a complex set up and tuning it can be a challenge. This component is part of general electronics, not specific to your DCC manufacturer, so I don't have to use the Digitrax product. I'll research this later and report the results here. A likely candidate is the Power Shield from Tony's Trains.

Power Bus

For each power district you'll have a power bus, consisting of two wires, using your largest wire gauge, that runs the length of the district under the layout.

I've chosen to use 14 gauge solid wire, red and black, for the bus. The wire size is influenced by two things: 1) the peak current (amperage) you expect to draw on the district at any one time, and 2) the length of the wire.

For (1) you can calculate the amperage by figuring how many locomotives you'll run and what their likely amp draw will be (some recommend using the stall current). This can be hard as so many variables are involved. However, one of the nice things about N scale is that locomotives, especially those manufactured this century, are amperage misers. We typically rate them at 1 amp maximum but rarely do they ever get close to half that (even most HO motors don't hit 1 amp at stall current). For my layout , despite a prevalence of track and locomotives, I am going to try using a 5 amp Digitrax command station for the whole thing and based on comparisons to similar layouts I don't think there will be a problem. If I do have a problem I'll have to get a separate Digitrax 5 amp booster for the upper deck. Because of the 5 amp limitation I used the value "5 amps" for my wire gauge calculations.

For (2), the issue is resistance. The longer the wire, the more the resistance. If the resistance gets you high you'll get voltage drop and the locomotives drawing power near the end of the bus will run slower than those close to the power source. However, you can counter this with a thicker wire gauge, since thicker wire has less resistance. (Note that wire resistance is not like the width of a water pipe. That is, if you have 20' of 2" pipe and 1' of 1" pipe, the maximum water flow is determined by the smaller pipe, and all that wider pipe makes no difference. But with wire resistance, as short length of small gauge wire, such as the feeder wire between the power bus and the rails, does not contribute appreciably to the overall resistance of the wire length.)

So, get your amperage, get the length if wire, then look up what size you'll need in a table to avoid the voltage drop problem. There is probably such a table on line somewhere, but I've found that no two sources of info on this are alike, due the the variables involved. For example, the table on page 104 of Andy Sperandeo's book Easy Railroad Model Wiring tells us that for 20' and 5 amps use 14 gauge and for 30' use 12 gauge (larger numbers mean a smaller wire gauge). However, another Model Railroader book, Mike Polsgrove's DCC Projects & Applications, says on page 13 that if you have a 14 gauge bus you won't need to consider 12 gauge unless your run is longer than 80'. Same publisher, different info. Part of the difference may be that Andy's book is about general electrical topics, with DCC covering only one chapter near the end, and Mike's is focused solely on DCC. As a test I ran trains on track that was about 75' from the power source, with 5 locomotives running at once, and there was no evidence of voltage drop. So since in practice my longest bus run will be about 40' 14 gauge should be fine.

I've been using 14 gauge solid (not stranded) wire, one red and one black.

I buy the 14 gauge wire (solid, not stranded) in red and black colors from the electrical section at Home Depot. You won't find this gauge at many hobby or electronic stores, and in any event it's cheaper at Home Depot because they sell it in large bulk to electricians (14 gauge is commonly used in houses for wiring circuts for lighting and common outlets).

When installing the power bus I now twist the red and black wire together. This is because if you have two parallel wires over a distance a nature impedance will form that can cause interferance with your DCC system. The twisting prevents that.

I use a cheap Dymo LetraTag label printer I got at Target to create labels for the power bus and wrap the labels around the twisted wire pair, usually adding a layer of scotch tape on top to assure that the label stays in place. For the buses the label is of the form: PD-1 (for Power District-1). I looked at various products designed for adding number tags to wires and found this to be a cheaper solution if you expect to create a lot of labels -- and they also look nice.

The next post(s) will cover my wiring standards for actually getting the power from the bus to the track. Later I'll discuss auto-reversing wiring standards.