Q: Does it work?
A: Kinda

Q: I can't place the outgoing tunnel entrance on the surface ?!?
A: Remove the signaling by cutting the rails to the mainline. Don't forget to connect it again after you placed the entrance

Q: Why are trains moving so slowly, especially manual driving ones?
A: At the moment there are problems with snapping to train stops, which forced me to limit the potential speed a train can enter a tunnel with. Manually driven trains are always slowed since I don't get an event like with the automatic ones for being enroute to a tunnel. This will hopefully not be necessary forever.

Q: Why do I have to add tunnels to the schedule?
A: Because there is no way to tell the pathfinder about them to allow for automatic pathing through them.