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.
2025-03-03 - RDC SP10 is back on the automated Branchline
Category RandallI just swapped the Rapido Amtrak 204 train on the Branchline, and reinstalled the good old Rapido RDC SP 10:
That little engine had been the workhorse of the automation, back in 2017 on the Mainline, and back in 2018 on the Branchline. It’s back again on the Branchline automation for a little while, to give some much needed rest to the Amtrak 204 engine.
The RDC SP 10 is a Rapido engine, and I gave it a pretty decent overhaul back in 2023.
The speaker was dead and got replaced. I originally replaced it with a 3rd party similar speaker I found (it’s an iPhone 4 loudspeaker style), and then later got the proper part from Rapido’s excellent maintenance support team.
The two motors were both in bad shape, not running well, and very much out of sync and no longer speed matched -- which is a common occurrence on these Rapido RDC units.
After I got new motors from Rapido, I proceeded to install the new motors, which is no small task. Except what I did is install only one motor. Since the engine now has only one motor, it’s a bit weaker and can’t make it up the grades on the layout; however the Branchline has only a very very small grade so it’s not a problem. On the other hand, there isn’t a second motor to get out of sync and fight with the first one, and it means I have a replacement if and when I need one more motor swap.
The decoder, besides being an ESU LokSound (they don’t really seem resilient in the long term), is doing reasonably well on these units. In this case, it has only one small residual issue which is that sometimes the engine stops responding to sound-off commands until it is power-cycled -- which will happen at the end of the day anyway when the museum staff turns off the layout.
The only issue remaining is that the RDC SP 10 derails on the new Branchline turnout replaced by Orion. Consequently, I changed the automation to have the engine stop at the station before the turnout. That means that I can’t program it to clear the branchline and allow a train to divert from the the mainline to the branchline.