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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.

2017-04-14 - Randall Passenger Train Brainstorming

Category Randall

Some brainstorming ideas regarding the issues with the Randall Passenger train.

The core of the issue is having two engines in push-pull configuration. When one loses power due to dirty track, the other engine is either pushing or pulling the whole train and it results in irregular motion that easily derails the whole thing.

Question is: Can this be avoided, yet still having two engines in push-pull.

Note: I am NOT doing any of this. Just thinking aloud about the problem and potential solutions.

Solution A:

  • Each engine and coach car picks up power.
  • What they need is to share that electrical power by connecting the black/red wires between each cars and engines.
  • This way there are 10 trucks picking up power, and it will be very less likely that the train loses power.
  • Cons: this is a hard mod to do. It requires to solder a little connector between each car and engine, which is hard to do.
  • Cons: It requires to plug them when assembling the train, which is also hard to do (like connecting a tender to a steam engine).
  • Some companies like Markling in their ICE train have special couplers that incorporate the plugs so that the connection is made when coupling the trains. This would not look prototypical and I have no idea if these are even available.

Solution B:

  • Instead of having 2 real engines, use one powered unit and one dummy.
  • The dummy can be a full engine with the DCC decoder so that it has sound and lights matching the front one. In that case it can be made into a dummy by removing the gear assemblies in the trucks and disconnecting the motor (but keep it in place to keep the same weight).
  • Cons: a waste of money on such fine equipment.
  • Cons: now there's only power pickup in a single unit.

Solution C:

  • Don't use DCC and instead use a system like S-Cab (
  • S-Cab is a recent system that uses radio-controller receivers *with* battery to control DCC decoders. The signal and the power is given by the radio and the battery and not via the rails. The rails are used to recharge the battery.
  • Cons: There's no way we could fit that inside the F40PH (not enough room, all the demos I have seen were on S scale or in On30).
  • Cons: I am not aware of direct computer control of S-Cab units like I do at Randall with the NCE.

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