I don't think Peter minds what time the night runs finish, nobody's done a night run up there before. He found the idea quite ... unique. He also laughed a bit too. I guess he's accustomed to TOYotas, that probably get bogged worse in the dark.
Personally I don't mind when they finish - you can go all night as long as you have fuel - but after midnight I'd suggest putting another $20 in the tin (new day, new fee) and any time after 10:00pm or so try to keep the noise to a minimum so the kids can get some sleep.
I'm a little concerned about emergencies when it's really, really late. I won't be on the radio much after midnight, so if something goes badly wrong up on the tracks there might be a real disaster. That's something I'd rather avoid.