Sounds like something that could be enforced by giving the passenger trains the ability to lock out switches further ahead of them. Like, say, an hour ahead of them. (Though, without signalling the particular switches that lower at-grade crossing guards. It’d be a rather fraught thing to engineer, all-told.)

Sure, you couldn’t run densely-packed passenger trains very well on such a system... but they’re not densely-packed. If they were, the system would have been a success and could then be turned off. ;)