>>1250418Nope. Some were used in reverse ( such as german class 42s ) but with a speed limit. Riding gear ( especially the non-driven trucks ) were almost always designed for riding in one direction. Front truck was to lead the locomotive _into_ a curve and the rear was to get it out and to carry the firebox.
Two exceptions are tank engines, of course, and garatts.
>>1250409No.
>>1250386There is thermal one. Longer pipes - more sealing issues ( live steam goes into cylinders at full pressure, so in the range of 200-300 psi ) more dirt issues and heat loss. Moreover - having a reprocating, sliding mass next to a source of dirt and dust, which the firebox is, is not a good thing.
Mechanically however - there is no issue. Garratts are an example.
