@VinceL posted:Would it be worth it (or even possible) to get a new TMCC board for the switch to restore full command control?
Yes you can buy the parts- next problem is the wiring harness between the 2 boards- as Steve eluded to.
https://www.lionelsupport.com/...STRACK-SWITCH-TMCC-B
https://www.lionelsupport.com/...FASTRACK-SWITCH-TMCC
Yes, you can easily use an SC1 or SC2 or newer ASC2 to control. That's what in some ways the original TMCC board is, 2 triacs that fire to short either the red (turn) or green (straight) wire of the controller to gnd (black).