(Formal term for trains and busses serving a line or between stations. Often used in the context of temporary changes to the track.)
How useful:
coming soon
2.
to mix with, to hang with, to have contact with
("verkehren mit" - In the sense of having regular contact with a group of people. Think of teenager having connections with dealers or someone regularly hanging with rich people. )
How useful:
coming soon
3.
to turn the wrong way around
(Very rare, and pretty much only used together with "ins Gegenteil.)