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About the Model Railroad

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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.

2017-02-19 - Progress on train automation at the model railroad

Category Randall

Work as started a few months ago on the layout and scenery is being refreshed.

In parallel, automated train runs are being installed. On two different routes, two trains are waiting to be activated at the push of a button. The trains go around a selected part of the layout, reverse and come back. While there's still work to do, here are two short videos demonstrating the early results.

The first route is a short passenger train composed of two Amtrak F40PH engines and Amfleet coaches that starts at the main passenger station. The second route features a single-unit Budd RDC (Rail Diesel Car) operating on the Branchline.

Video of the Passenger Automation

Video of the Branchline Automation

2017-01-16 - Thinking ahead on the Automation Software

Category Randall

Here's a rethink of the automation software.

Right now I have JMRI for sensor management and DCC throttles. Conductor acts as a plug-in that drives the automation purley on sensor+timer event based script.

One useful thing in RocRail is the notion of routes, which JMRI has too of course (but annoyingly complex to setup).

The idea is to describe the model railroad using a chain of blocks with turnouts on or between them.

The timer/sensor script remains the same, but the goal is to have the software know which engine number is on which block. This in turn will drive the display and make it possible to lock routes.

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2017-01-16 - Lights and Sound

Category Randall

Just brainstorming here.

Power on the lights : steady when buttons are enabled, blinking when running (or the reverse).

  • That could easily be done with an Arduino.
  • Or by using a Switch-8 and an NCE Dual Relay (if it were steady only, I would not do blinking with that).
  • How does the Arduino receives the orders?
  • ⇒ Might as well use an ESP2866 with wifi.

Optionally emit speaker sound.

  • There are some RMC speakers in the back (save them so they don't get trashed).
  • Something like a DigiX with a speaker output and wav files loaded from an SDCard.
  • Even simpler: use the JMRI computer, audio output split in 2, e.g. right channel to speaker under Passenger, left channel to speaker under Branchline.

2017-01-04 - NCE Button Board

Category Randall

After talking to tech support at NCE: the Button Board has a bug and they don't support non-momentary switches like the rotary toggles we use. It MUST be momentary.

<cold shower>

Proposed hack to verify: add a push button on the common ground of leading to the rotary toggles. Operation mode is thus turn a toggle then push the button to simulate a momentary push.

Longer term: my first reaction is to just simulate the Button Board using an Arduino. Must take 16 digital inputs and emit the proper 2-bytes sequence over serial.

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2016-12-28 - Relay for Fulgurex T330

Category Randall

I ordered this: 

Relay: TRS-12V-SA-L20

Datasheet: looks similar to this 

On the bottom there's a pinout drawn that is similar to the pinout from the datasheet:

  ⇐ This is the BOTTOM view. Invert vertically from top.

How to wire it for the layout:

2016-11-18 - Non-Tortoise Slow Motion Turnout/Switch Motors

Category Randall

After repeated failures at trying to control the T330 turnout using an NCE Switch-8, I finally crawled under the layout and I find this:

That is definitely not a Tortoise turnout motor, which is what I had been planning for all along.



Turns out the layout uses:

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2016-10-23 - Simulation & Programming

Category Randall

We did a "simulation" yesterday at Randall using JMRI, a simple Jython script and time-based automation as indicated previously.

For the Passenger automation:

  • We used the half/full/half speed scheme.
  • Block-wise, the idea is to stop on 370 on the Summit.

For the Branchline automation, Jim decided on a "full speed" scheme, relying on DCC momentum.

Whenever possible I'd like to use block detection rather than IR sensors. It may not be a choice for the Branchline, but that remains to be seen by crawling under the layout and decoding the Branchline panel more closely. If not, I'll do IR sensors.

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2016-10-08 - NCE USB Limitation

Category Randall

Simply plugging the NCE USB to Power Pro resulted in no status from AIU card whatsoever.

Consensus is that will never work on the USB (when it ironically works on a PowerCab, but only with one AIU on cab address 4).

Bottom line for Randall I'm going to have to switch to RS232 with a USB adapter.

  • All forums and sites point to the same Keyspan USA-19HS adapter:  … $25.
  • Need a Straight (not null modem) RS232 cable, 50 ft will work here.

2016-09-25 - Turnouts Control

Category Randall

This is where what should be simple becomes overly complicated.

The easy solution is to use NCE Switch-It (1 tortoise) or Switch-8 (8 tortoise) control.

There are a few issues.

This takes power from the track bus or external supply.

  • Know issue ⇒ Do NOT take power from same booster powering the same block that is being switched. If there's a short when throwing the turnout, it will remove power from the switch-8 which consequently won't be able to finish switching.
  • Power MUST be from either a different booster OR use the direct DC power plug.

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2015-12-25 - Non valorem in ruinam

Category Randall

The GGMRC officially donated the layout to the Randall Museum.

L'important ce n'est pas la chute, c'est l'atterrissage.

Now it’s time to (re?)build a relationship and get this going.

Freeze frame. How did we end up in this situation?

The opinion below is solely my own and not the official views of the GGMRC. It is based on my own recollection of events and my own biased opinion on such events.

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