Abstract: A drive system and mounting system for an vehicle mounted alternator is provided wherein such an alternator system may be mounted to the structure directly above the axel/bearing combination by means of a mounting plate and associated spacers that are is adaptable to a wide range of rail freight cars, associated bearing adapters, bearing sizes and types, and side frames. This alternator system employs automatic tensioning devices similar to those in automobiles and is enclosed to provide protection from the elements and vandalism.