What buffer for solving delays would you consider acceptable for that mode switch? Train schedules are inherently fragile because there's so much interdependenc

What buffer for solving delays would you consider acceptable for that mode switch? Train schedules are inherently fragile because there's so much interdependence. Every tiny bit of the trip is locked into a signaling segment block time slot and one train causing a shakeup leads to wild butterfly wing effects fanning out in all directions. Rail networks in places that have more than just a trivial amount of service tend to run very close to saturation, even if they don't look like that at all. But you can't cram trains on a line like you can cram cars on a highway (or planes in an approach pattern), that's just not how safe signaling for wheel-on-rail works. And no, I won't accept "but it works in Japan!" as a counter, because Japan does not really have anything resembling a train network. They have a number of lines going up and down one corridor, plus two appendices branching off to the west coast. Compared to that, even the French star of lines separated by metro rides appears complex.