Comment by kazinator

> Is it written in stone that a train must fit entirely into a station so that all doors face the platform and can be open simultaneously?

When you're building high capacity transit for dense cities, yes. You could stop the train twice in the same station, sure, but at that point you have to stop for twice as long (probably a little longer than that as your riders will get confused), so your train takes ~twice as long to get anywhere and can therefore carry ~half as many people.

Some metro lines have this (stations too short to fit the whole train). It is _not ideal_. Like, in some cases it's probably unavoidable, but it would not be your first choice, from a passenger ergonomics pov.

It is really a safety and dwell time thing.

The moment you have only some cars platforming, then people need to make sure they are in the right car, and if, say, a slow-walking elderly person is in the wrong car, then her getting into the right one to get off wastes a lot of time.

It's not written in stone, but if you don't, people will be moving through the train and pushing to get out sooner. Public transit is a test of patience and a study in human herd behaviour.