Making a figure move

Try a servo as used in the radio-controlled hobby. They can be obtained in extremely small form factors.

Yep, the RC servo and a small microprocessor to generate the PWM signal to properly move it would actually not be that difficult to do.  The trick is fitting it into something like a steamer cab.

PeterA, you might want to check out and join the Facebook group: Arduino for 3 Rail O Gauge Model Railroaders. It's all about learning to use microprossers to program LED's, Servos, and many other things to do exactly what you want it to do. There are also YouTube videos that teach about using Arduino microprocessors, and a good book that you can download for free is Arduino for Dummies that teaches and explains it very well.

Gunny:

Can the motorized "guts" of a servo be powered directly, without the necessity of injecting the PWM signal? I am thinking of an application for opening couplers on radio-controlled locomotives, without having to use up the limited number of channels on the RC receiver.

Sure, you can use any "trigger" to do the job.  Somewhere buried on the board here I did a simple one years ago for the Tie-Jector.  Instead of using track trips, I used a model airplane servo and just made a little 555 timer board that moved the servo a set distance on command to start/stop the tie dropping.

Here it is: Command Equipped Tie-Jector, this is the board.  I triggered it with a coupler trigger as I recall, the relay is to isolate the coupler from my electronics.  WOW, nine years ago...

Rusty

Wow, you guys sure how to make things complicated. RickO posted a video by Laurie Mclean. Search youtube on more of his videos. This is simple stuff.

https://www.youtube.com/result...laurie+mclean+trains

Pete