In a related area, an offshoot of Xbee research I guess, I’m hacking up a $35 Hobby King transmitter and turning all the channels into knobs. It’s a simple matter to remove the joysticks, each axis is a 5k pot. I have a bunch of cheap 5k pots I got from mouser for another project that I can use for this application. Once I have the circuit working, I’ll make a 3D print of a console to hold the electronics and use that to control 6 trains with one transmitter. Probably better would be 3 trains plus two discrete functions per transmitter but either way, it’s an easy mod. I’m pretty sure I can sync 3-6 receivers to one transmitter, but I will get a couple to test with soon just to make sure. Using an ESC with reverse, it should be possible to control direction and speed for six channels of trains with this.
October 27 2013:
This progresses, I’ve decided however to not use the pots I had and instead use 3 from Radio Shack to make mounting them easier. I’ve also decided to take this to three throttle controls with several push buttons for the second channel.