Trying not to disrupt the Railtruck thread, but when I was trying to find when rail trucks came into existence I of course came across rail buses.
Although rubber tyred railways were discussed, Adelaide’s weird Obahn was not mentioned on the link, so I thought I might share the weird bus track we have here.
There is a guide wheel in front of each front tyre.
It engages the concrete track curbing.
In the good old days, the bus driver would hit highway speeds, let go of the steering wheel, count money or tickets etc, then re-engage with the steering wheel at the next stop.
When broken down there is a busway push me-pull you rescue truck.
Sometimes we get cars that identify as o-Bahn busses.
Another Link 
