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About the Model Railroad

RTAC Software


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.

2019-04-07 - RDC Santa Fe on Branchline Automation

Category Randall

The Rapido RDC Santa Fe has been working nicely on the Branchline with the automation for a few weeks now:

Click on player above to play full video.

These are the latest Rapido RDC Santa Fe, numbers 191 and 192. I had to adjust the front plow as it was riding too close to the rails and actually binding on some flex track junctions. I also did their “break in”, and performed the LokSound “slow crawl” adjustment as well as adjust the volume.

For more history on these unique RDCs, please visit this site: They have a unique story and is quite worth reading and this site actually explains why both cars are looking different.

I’ve also made a video of it on the mainline, for a bit of variety:

One thing we’ll have to keep an eye for are dirty wheels, and dirty track. We have no shortage of both. Since both engines are powered, I’ve noticed on dirty track one engine might get a speed change or stop command while the other one may not. This can result in an engine trying to push or pull the other one.

The automation has a specific handling to avoid just that: it repeats all speed and stop commands every two seconds. I came up with that to solve the push-pull issues I was having with the Amtrak train on the mainline. In case an engine failed to get a DCC command due to dirty track, it would get it again a couple seconds later. This is enough to resolve any such issues.

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