There are nifty little DCC decoder chips that are so small they can be installed fully within turnouts and make them addressable from the computer, drawing power from the track. But they're expensive and you need 1 per solenoid otherwise they would draw too much current, and this thing has 4 solenoids and I want several double crossovers. So had to find a cheaper way.

All you need to do is pulse the solenoids briefly which is easy with a motor driver and this one can supply enough current.

Handily, this chap wrote a mini library to handle the timed pulse in a non blocking manner which will be useful because the arduino will also be running the RF24 Network library to communicate with the computer.

Easy peasy.

However I seem to have broken my radio module so no radio stuff.