Thanks for the advice - I'll look at the methods you all have pointed out
as for the AC part, if you look for model railroad switches, they have a part called a 'frog' which has to match the polarity of the correct rail, so on DC it has to switch from -ve to +ve and vice versa, and with new DCC control systems that use AC has to invert the voltage
have a look at this
https://www.alfray.com/trains/blog/train/2020-03-08_dwarf_signal_for_turnout.html