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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.

2022-05-06 - An Update on the Branchline Automation

Category Randall

The Branchline has been running the Rapido Santa Fe RDC 191+192 for quite some time. Then it was 191 alone as the other engine stopped working. And then there were none.

Jim suggested to try something different so we did:

I apologize for the poor video & sound quality as I shot this on the phone.

This is running a MoPac #153 2-8-0 Consolidation engine. It does sound great, although running characteristics are not ideal for the slow speed needed for the Branchline.

The other issue is that the track on the Branchline is quite subpar, it’s not always as flat as it should be, the dual-gauge turnouts are tricky, and the track has just too many quirks. For example one is very visible in the video above when the engine starts from its interchange storage track, there’s a very visible elevation change when crossing some of the yard turnouts. Then in the canyon tunnel, there’s a kink in the track -- 2 segments of flex tracks that have been soldered not straight, forming an abrupt angle. It’s enough to derail quite a number of light cars or engines.

I then spent a couple hours updating the automation script to run #153 on the Branchline.

The bottom line is that this automation attempt was unfortunately short lived. The engine lasted one day in automation. Then it derailed on one of the turnouts and one of the trucks got damaged. RIP.

Going forward, I am going to strongly advise against steam on the Branchline. The complex wheels of steam engines are just not ideal for the track subpar quality. Especially very light front pilot trucks derail easily. Years ago I “solved” that on a 2-6-0 by removing the pilot truck and running it as a 0-6-0.

However even with such limitation I’m not sure the Branchline is appropriate, and we should probably stick to B-B diesel engines, or long wheel-base engines like the Rapido RDC or similar commuter rail engines.

So far the Branchline has killed no less than 3 Rapido RDC engines, which in its own way is prototypical.

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