A well built Railbus could server as a multipurpose vehicle, Pass Car, MOW, and would make it possible to operate trains with a min crew in times such as now.. (I guess the D&S Railbus gets it's workout now!?)
Of Course, an existing coach can be used, especially the ones made from the Fishbelly flats...What you need is the power truck assembly, new rear truck (pass style..)build cabs, and voilĂ .....a Low cost railbus....or do as they did in Central America... get an old Mack schoolbus and put it on NG trucks.... an even lower cost Ferrobus, not as powerful, but mejor que nada..
Of course the EBT #1 would be nice too...
Boris