The factory fresh SD - 7 had the classification lights on a door inset from the ends, in the middle of each angle of either hood end. The design of this classification light door allowed water to leak into the interior of the ends, and also the sandboxes. EMD fixed this issue on the SD - 9 by welding a frog eye - type class light housing to the ends, very close to the edges. While this design fixed the water leak, it also required a mechanic to change a burnt out bulb from inside the hood.
Espee SD - 7's, unless equipped with a steam generator, were usually missing the forward tank. Some ex - passenger SD - 7's had the front ( water ) tank converted to diesel fuel, however all emerged from Sacramento rebuilding with only the rear fuel tank and 1500 - series numbers.