For most of the route, they cannot pass one another.Same with the 220, two following each other How does that even happen?
If a road is wide enough and if the first bus pulls in, the one following can pass, assuming that no one on that second bus is getting off at that stop.
The bus 2 becomes bus 1 and he now is the first to arrive at the stops so he stops and after a while the other catches up again.
When they get to their destination terminus, Union rules kick in and they have their break.
Once the brake is over one will go off service and will take a short cut back to the middle of the route and then resume the route from there.