This is a shell to convert an Atlas C40-8 into a C39-8. This is the version of the C39-8 purchased by Conrail and what also ended up on Nofolk Southern and CSX after the split of Conrail.
Condouctor side battery boxes are also provided if you wish to change those to match the prototype but is not necesary to do so. The shell is a direct fit to the C40-8 walkway but a little trimming is needed on the shell in order for it to seat properly. To obtain a more correct fuel tank I recomend using the fuel tank from an Atlas B40-8, those tanks can be bought directly from Atlas.
To clean the shell soak it in Bestine rubber cement thinner untill the shell turns an opaque white, this means the support wax from printing has been removed. You can also buff the shell to remove any fuzz around the details by gently scrubbing the model with an old tooth brush and tooth paste.