One issue with the start/stops is "jackrabbiting" of restarting from a stop and wait. The inrush of power can be slowed or the voltage to the "dead track" lowered slightly at it's drop wire by paired opposing diodes, inrush limiters/ resistors, etc.
There are command control options for "recordable actions". Both cabled and wireless. Most command systems offer some version of it. Basically the track gets full power all the time. Then a system sends a throttle or sound, etc signal to each engine/item and the engine/item obeys. The systems use the rails, and/or "radio"(of numerous types) to send the signal(s). The more you invest in the system 'brain'; the more you and it can do.