I can think of two examples. In LA there are busways that are built on former train paths. When they need to divert for whatever reason (road repairs, special

I can think of two examples. In LA there are busways that are built on former train paths. When they need to divert for whatever reason (road repairs, special event routes, etc) they can just make a turn and act like any other bus. Something like the Hyperloop car carrier could work here or at the very least an expansion of bus ways could provide train like access with a lower infrastructure cost. Amtrak will also let a certain number of vehicles onto some of their train lines. I don’t know how well that works, but it seems like for a well run popular route you could have a ferry like experience.