I used to live beside a commuter train elevated line (in Ireland, not Japan). Many nights after the line shut down, there’d be at least some maintenance going o

I used to live beside a commuter train elevated line (in Ireland, not Japan). Many nights after the line shut down, there’d be at least some maintenance going on, sometimes extensive maintenance. And that was just on the short stretch I could see. Heavy rail takes a fair bit of maintenance, and 24 hour buses can _mostly_ plug the gap in places that have them (volumes are way lower at night). Irish Rail sometimes runs late services around Christmas and New Year, but have been fairly clear that it’s not sustainable, and even then there’s an hour or so gap where the tracks are cleared before normal service starts up around 05:30.