Railbuses were fairly common in the 30s as a form of interurban. They had regular tires for roads, and a controllable hydraulic system to lower rail wheels for running on rails. They could jump onto the track at a level crossing, run on the track for longer distances, then jump off and get around town.
British Columbia is considering a return to the setup for some isolated towns with abandoned tracks. The new buses work just like the old.
Polistra's Mill 