There is currently no way to connect train tracks to an electrical device. You can use devices like a switch while riding a train track, but you'd have to have the player manually flip it while riding. The other option would be to try placing a pressure plate near where the player might ride, but I don't think they would be over the pressure plate long enough to fully open a door. I'll have to think on that one.
I do have plans for speed boosts and brake sections for the train tracks; maybe there could be like a switch type track that electrifies whatever it's connected to. A better option might be a laser "trip wire" type thing where whenever a player crosses it acts as a switch of sorts. Then you could just have that where the player will cross it, and I think that would cover your use case?