Bus.
A vehicle that operates on a cable, usually on the ground. Aerial cable cars may be of the type GONDOLA_LIFT.
Commuter rail.
Ferry.
A vehicle that is pulled up a steep incline by a cable. A Funicular typically consists of two cars, with each car acting as a counterweight for the other.
An aerial cable car.
Heavy rail.
High speed train.
Intercity bus.
Light rail transit.
Monorail.
All other vehicles will return this type.
Rail.
Share taxi is a kind of bus with the ability to drop off and pick up passengers anywhere on its route.
Underground light rail.
Above ground light rail.
Trolleybus.
See
https://developers.google.com/maps/documentation/directions/intro#VehicleType.