Bachmann's first N-scale geep is this EMD GP40 diesel locomotive. It is interesting to note that Bachmann re-tools their GP40 and F9-A units just a few after introducing them. The original Bachmann N-scale GP40 suffers from being too wide for scale proportions. I measure the long hood at 8-feet wide for the original tooling.
The revised tooling is reviewed by Model Railroader in the September 1969 issue. The review spotted the hood as being 7-feet wide, rather than a scale 6-feet wide. The magazine review also points out the undersized fuel tank. Model Railroader also labels the handrail design "unorthodox." The handrail design is found on a handful of ready to run N- and HO-scale models of this period. Perhaps to make them more durable, the handrail stanchions are cast along a strip of plastic that snaps into the sill of the shell. The strip runs from end to end along the side fo the shell. You'll find this not only on this N-scale Bachmann GP40, but also the HO-scale example. It is also found on certain Yugoslavian-made Mehano offerings and Life-Like's HO-scale GP38-2.