In the June 2007 edition of Wired Magazine, they had a tidbit on a new Japanese hybrid mass transit vehicle.
It's being developed in Japan. It's called a "dual mode" vehicle. It rides on rubber tires, until it reaches a rail line, where steel rail wheels drop from the undercarriage in under 15 seconds, and boom, it goes from being a bus to being a train. It's currently being tested by the Japense Regional Railroad.
Among the touted features is it uses less fuel and requres less maintanence then a regular train, and could be used in areas where train service isn''t feasible but a connection is needed.
Wonder if the technology will ever make it over here? I know this could really be useeful in putting LA's difficult mass transit system together more.