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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.

2018-09-01 - Self-healing Derailment

Category Randall

Here’s an interesting way to not do train automation:

I had been at the museum to examine the RDC in the morning. The passenger train had two coach cars. Jim came by during the afternoon and suddenly ask me if I removed one of the coach cars since the train had now a single car. No I didn’t. How was that even possible?

Jim tried changing the automated passenger train to use just one leading engine (Amtrak #506) and two coach cars. Cars were carefully weighted and made sure they would stay on the track. They worked flawlessly for a week.

I’ve set up a wyse cam to monitor the trains; often the best way to know if the automation works or more exactly how it fails is to just record and look at the footage. That was a really good catch here.

What happened? The first coach car is seen as being wobbly out of the station. The second car uncouples, followed by the first one falling partially off track. The engine continues its back-and-forth route. On the way back, it pushes the derailed over in the ravine and couples to the car that had remained behind.

The automation continued working nicely for the rest of the day using a single coach car.

The irony of this is that I had recently been working on modifying the automation program to detect the engine failing to reach its destination and then stop the train, but I just hadn’t installed the modified program yet. I installed it today so that should not happen next time.

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