That probably depends on how many rails and when trains can cross onto other rails. I.e. a basic flow is all trains go one direction on one rail, and they all

That probably depends on how many rails and when trains can cross onto other rails. I.e. a basic flow is all trains go one direction on one rail, and they all go backwards on the other. You can use the "wrong direction" rail to pass another train, but only if there's no oncoming train. Waiting for a train to go through so you can cross is effectively the same as stopping at a station. The answer is to have more rails, but that takes more space, and I'm not sure how much space they're dedicating to the rail system. Rail scheduling is fascinating; it does make me curious how fast they can make this system in a real world environment.