Originally Posted by
Heathrow Harry
You don't get passengers trains that convert to buses - although there are "guided bus-ways" in some cities
Generally the extra weight and cost of designing for two or three different transport modes greatly outweighs the efficiencies of a single optimised design
Actually you once did. In Germany after (during?) WW2. Saw them when I was at school there.
Somehow the steel wheels retracted and the rubber ones came down.
Might be useful if somehow there was a bit of rail missing.