Most of Tokyo's mass transit network is absolutely neither isolated nor enclosed, and operates with vastly higher frequencies.

Here's is the timetable for a suburban station on a commuter lines: https://train-cloud.navitime.biz/en/odakyu/railroads/timetab...

On a weekday at peak hours, there are up to 20+ trains an hour, with commuter trains continuing directly into Metro systems, and directly onto different commuter lines on the other end.