Hey @jawnjawn,
Im not sure I understand what you mean by RP train, is the point of this train something you (a player) is setting up, and you want it to run infinitely?
or you (an admin) want to spawn a train, then place shops, and have this train go infinitely?
In Either case the train will ALWAYS turn off if going faster than 0 and no players are onboard. There is a convar you can disable to prevent this, however I could not recommend it, since if a player falls off their train, they wont be happy!
the only time the train stays on is when at 0 (even when no players are onboard)
I would suggest finding another plugin that accomplished what you're looking to do more seamlessly, maybe ArmoredTrains?