When the Aristo GP40 was released there was a post on the Aristo site about the possibility of making a SD40 out of an SD45 and the new GP40. I did a little research and decided it would be a fairly simple kitbash. I chose a S.P SD40R as my model as they appeared in the 1990's. The one I chose to model was built in 1966,upgraded to a SD40R in the early 80's and then upgraded again in the 90's with S.P speed lettering,new MU connectors,new coupler release levers,ditch lights and the removal and/or plating over of the S.P. light package and classification lights. Although an SD40 looks kind of like an SD40-2 they are different animals. The SD40 is 65' 9 1/2" and was actually built on the SD45 frame. The SD40-2 was built on a new frame that was 68' 10". To get a basic SD40 out of the two models is really fairly simple. I just cut both the SD45 shell and the GP40 shell just behind the filter and blower housing on both shells. The remaining long hood portion of the GP40 shell was then fitted to the front portion of the long hood from the SD45. The dynamic brakes are a kitbash of the units from both models. The front left and right handrails were also extended and another stanchion added. Beyond that it is just a matter of how far you want to take the detailing. The graphics were done by Stan Cedarleaf.