Nice idea but..... Hm not quite sure that Track Pickup would be such a good idea as pickup via a wagon can be quite flakey giving inacurate readings I would think.AND.......
(bet you wish you had not 'stuck your head above the parapet'!?)
Pick-up from the track, for us DCC types.. Would just need a bridge, 'buck' regulator, and an off/on switch..
Pretty please?
JonD