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The Randall Museum in San Francisco hosts a large HO-scale model train layout. 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 de-facto layout 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.

2019-02-22 - RDC ATSF, Branchline, and old Turnouts

Category Randall

Tonight’s first attempt to run RDC ATSF 191/192 on the branchline started well. I ran the engine from the mainline to the branchline by using the interconnexion and that worked well. I reprogrammed the automation to use engine 191 instead of SP 10 and that worked flawlessly since they have the same running characteristics. Then the RDC derailed on the way back, consistently at the same location, and this is what I observed:

RDC ATSF 192 approaches Angels Camp station on the branchline.
The branchline feature these complex dual-gauge turnout, being both standard gauge and narrow gauge.


Some engines or cars work well here, and some derail. Every. Single. Time. By looking at it more carefully, it’s painfully obvious the bottom point is broken in the turnout, and the top one has a small gap.

This is of course not an isolated case, and I hope to be able to save the situation temporarily by spiking the point on this turnout. However there’s would the 5th one that suffers this way on the layout, and out of these there are only two that I believe I can actually fix. This is a typical case where I have no idea how to fix this in the first place. Electronics and software, that’s my thing. Adding a metal bar at the right place… that’s not. Or to put it another way: I could try to fix this yet I know I’d just make it worse, so there’s really no point (pun intended) in even trying.

It’s not even a new thing. I rewatched this video I made in June 2015, and that point can be seen clearly broken at 6:19:

Screenshot showing the broken point.

Click on player below to play full video.

That’s a bit disheartening as I was hoping to use this turnout and control it from the automation. However that’s ok, there is another turnout I can take advantage of.

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