[closewith]

Which makes sense, as the next one may be equally or more overcrowded. In a busy urban area, it may be hours before an uncrowded train arrives.

[derdi]

I'd argue that that's not bunching, it's the entire system being overloaded. A characteristic of bunching is that you have a pair of vehicles which together carry an average manageable load of passengers, but that load is unevenly distributed between them.