I know Noel Reed is a promoter of the "train-tram" concept.
I recently came across this "bus-train" unit, a former promotional creation
off a London DMS bus, now preserved at the Epping-Ongar Railway near London.
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQXhFH0tBOnm4q-No_CQ2rv
mu8Hb23SDOAtXDhBkXZqcorPzOoJWQ
https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcRelTGMLH45iK2V08yBOUBZ
HWmIxo-yU2NrI0StRYvS62EatBON_g
Hope these links work, if not you can find them, and more, in Google Images
under Epping Ongar Railway
Brian.