For right now, the trains "claim" the switches on their route between one stop and the next as the leave the stations. If one train leaves a station and the other is already in route, the new train will claim the switch direction. Reducing the distance between the stations and the switches helps, but will not completely solve the problem; Even if the station serve no other purpose than to control the switches. The shortest section of rail you can lay is about 12m. AFAIK, they only claim the switches they need to divert, but have no effect on switches that merge back.