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The Randall Museum in San Francisco hosts a large HO-scale model model railroad. Created by the Golden Gate Model Railroad Club starting in 1961, the layout was donated to the Museum in 2015. Since then I have started automatizing trains running on the layout. I am also the model railroad maintainer. This blog describes various updates on the Randall project and I maintain a separate blog for all my electronics not directly related to Randall.

2022-02-19 - Room Ceiling Lighting

Category Randall

Some work has been made on the string of fluorescent lighting on the sides of the room. The two strings of ceiling fluorescent tubes with their 60s-era ballasts on both sides of the room had all mostly failed over the last four years, rendering the two side alleys quite gloomy.

All the credit goes to Chris, Director of Randall Museum, who performed all the work on his own, independently of our regular volunteer maintenance work.

A month ago

Today

It’s notably better over Stockton Yard and the middle of the mountain area -- the before/after pictures don’t quite express the stark difference since the cameras obviously compensate for overall luminosity, however it’s quite clear there are a lot more shadow areas on the before pictures.


2022-02-15 - Randall Repairs: Turnout T161 (4th fix)

Category Randall

Affected

Turnout T161 (end of siding between Bridgeport & Sultan).

Description

Intermittent loss of power on frog.

Summary Fix

Add bond wires to power turnout stock rails from B161.
Bypass the frog polarity contact/inverter. Deactivate turnout (always straight).

Description of Issue

For a while we’ve had issues with the turnout T161. Trains would stop dead on the turnout. Other times they worked fine. Some trains could go through just fine yet we would have issues with steam engines.

Back in 2018, I identified the frog power showed a clear resistance, and posited it was due to faulty contacts in the Fulgurex. After changing the switch machine in 2018, the problem went away. Then since last year we’ve had intermittent issues again with this.

Two weeks ago, I did two things. First I hardwired the turnout for the straight route. Now the frog is always powered directly from the proper stock rail. The switch machine contacts powering the frog are entirely bypassed. The other thing I did is take an overhead picture of a similar turnout and color the rails to clearly understand the power routing of the turnout.

The “fix” from two weeks ago did not last long. At the next operating session, trains stopped on the turnout again. However this is good as it helped eliminate the Fulgurex as the culprit. It is not an issue of frog power routing. We also know that the turnout sometimes works fine, so I suspect a bad solder join or something similar on the way the turnout gets its power, something that varies with time & temperature as the track can expand or shrink -- a problem we have in a few other locations on the layout.

Here’s a picture of T161:

And here’s the same picture, annotated to understand power routing:

Now I understand how this all works:

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2022-02-09 - Turnout Frog Power Routing

Category Randall

Now for something a bit different… understanding power routing on turnouts as used at Randall on the mainline.

This replies to a question I had recently, and eventually I’ll add it to the Randall Layout documentation because it’s good for future reference. Once again I was tempted to write here an explanation of why turnouts are wired the way they are, yet that would be long and convoluted. For that, I’ll just refer to the excellent material at https://dccwiki.com/Turnout which is complete with detailed schematics and presents the various ways a turnout can be wired.

For our mainline turnouts, here’s a concrete example by taking an overhead shot of Turnout T05 and coloring the rails A and B and all the parts which are electrified the same way:


Turnout straight/normal.


Turnout thrown/diverging.

Non-isolating power routing turnout:

For reference, this style is called a Non-Isolating Power Routing Turnout: the entirety of the frog and the closure rails are one contiguous section and are all powered depending on the position of the turnout. Two wires bring power from both rails A and B into the switch machine and a contact moves to select power from either rail A or B and powers the frog and the connected closure rails accordingly.

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2022-02-08 - Train Vision Computer Update

Category Randall

The original Vision computer is back on the layout, running the latest version of the train-motion software:

I had issues with that Lenovo Yoga 15 at the end of last year and I quickly exchanged it for a smaller X1 I had as a spare at home. I’m glad to be able to have the Yoga 15 back on the layout as the screen is larger, and it’s also the most ridiculously good looking screen I’ve seen on a Lenovo line so far. Super sharp, rich in color and contrast. It really shines in this video display application. I don’t want to diss my beloved Lenovo X1 screen, it’s just that the X1 screen is matte and really works well for work and long coding sessions, whereas the Yoga screen is more vivid in color and obviously targeted more at displaying videos.

Here’s a description of the display when running the train-motion software:

On the picture, Live Cam 1 has a yellow highlight around the video to indicate that motion has been detected in this live video stream, and we can indeed see the yellow UP passenger train in view.

Eventually I want to move the cameras 2 & 3 to more interesting parts of the layout, yet before I can do that I’m waiting for the museum’s maintenance staff to fix the overhead lighting issue.


2022-02-06 - Randall Repairs: Turnout T161 (3rd fix)

Category Randall

Affected

Turnout T161 (end of siding between Bridgeport & Sultan).

Description

Intermittent loss of power on frog.

Summary Fix

Bypass the frog polarity contact/inverter. Deactivate turnout (always straight).

Description of Issue

Back in 2018, we had engines stop-and-go on turnout T161 for quite a while, especially steam engines, or short non-MU engines. The turnout was always in the normal position when this happened. Back then, it was determined the frog power routing on the Fulgurex created a resistance. This was solved in 2018-12-12 by replacing the Fulgurex. The issue re-appeared last year, and it was “fixed” by Allen spiking the frog in place. This worked for a while, and now the issue is reappearing again, with trains going dead on the frog.

Frog issue: Issue is frog power via the Fulgurex contacts. Last time, it was solved by swapping the Fulgurex. Eventually the contracts just oxidize or present some kind of resistance, likely to complete lack of use. And we cannot throw that turnout since the throw bar has been spiked.

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2022-02-02 - Turnout T161 and a Philosophical Discussion on Having Too Much Track

Category Randall

We’re having a “dead spot” problem at turnout T161. Again. For the 3rd time.

I was going to ramble at length on the complexities of turnout designs and what causes them to short. Instead I’ve decided to skip that because https://dccwiki.com/Turnout has much better graphics, and better explanations. So please go read that.

One thing I do not know for sure is what kind of turnouts are installed at Randall. I should know. And document it.

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2022-01-16 - Randall Repairs: Turnout T111

Category Randall

Affected

Turnout T111 (after Fairfield station, arriving at Lodi).

Description

Point loose. Specific steam engines derailing..

Summary Fix

Spike/glue the point.

Description of Issue

We’ve had some specific steam engines derail here in the past. It was identified the point rails were loose because there is no turnout throw rod at all. Previously the point rails were spiked.

We recently were having problems again with some specific engines, this time being this BLI 844 Challenger. The suspicion was that the spike may have been too high and derailed the engine.

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2022-01-11 - Train Vision Detection and Perfetto Tracing

Category Randall

Back in November, I did a major update to the train-motion software that drives the Vision computer at the museum for the Train Vision Project. A major issue was the image detection had a lot of false triggers and would erroneously detect a change in the image when there was no motion. I reworked the image analyzer, and I also added logging to capture what motion is detected. The logging system dumps data to a JSON file compatible with the chrome://tracing protocol and the Perfetto web UI, which I can then collect remotely and analyze later.

Here’s an example of run from last Saturday:

What we see above is an automated run from the mainline Freight train. Rows represent cameras 1, 2, and 3 respectively. Let’s look at camera 1 in detail:

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2022-01-10 - Planning for 2022

Category Randall

This year I’d like my projects to enhance the automation. There are two automation additions I want to get to, namely Fairfield and the Trolley line; however I realize these require a lot of research & preparation work that is mostly software and, if I go there, it will be yet another 6-9 months with nothing tangible for others to actually see.

So instead I’d like to focus on enhancing the variety of the current automation.

1- Branchline Automation

We currently have a single engine running, and we park it on the B811/B801 storage track. However the track & panel supports 3 storage tracks.


Branchline/Mainline Track Diagram (blue is mainline, green is branchline).

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2022-01-08 - Documentation Update and a Trip Down Memory Lane

Category Randall

I’ve spent some time updating the Documentation git repository. What’s changed:

  • There’s a new hardware folder.
    • Currently it only contains the PFM Fulgurex documentation.
    • I plan to add more to collect the user manual of all the hardware we currently use on the train layout, from the command station, to the various electronic boards such as auto reversers or electronic circuit breakers.
  • There’s a new ggmrc_history folder.
    • This contains paper documentation I found on the layout’s archives. I scanned them all a few years ago. Scan quality was so-so; image contrast is really poor on many of these. I tried my best to find what they describe and rename them accordingly.

I was particularly interested in the historical documents I could find. They cover a wide time range, from 1965 up to 2010.


Layout wiring standard “adopted June ‘65”.

However these documents are a mixed bag. Some are early design schematics for the mainline or the yards, which may or may not be relevant today. There are some early construction standards for the layout. Others describe equipment which is not there anymore. There are a few yard or panel descriptions that I could not quite relate exactly to the layout, so these are labeled as ‘unknown’.

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