In looking at old EMD GP9 locomotives, it's plain to see that some have no dynamic brakes, some have dynamic brakes, and some have torpedo tubes. I have often heard these called "passenger" versions. Is there some specific thing these torpedo tubes do to help with passenger train needs, or is it just that these tanks are moved to the roof to give more room for, say, a water tank down next to the fuel tank? (This is my guess, not a statement of fact.) Thanks, Adam
Larger fuel tanks (1,100 gal larger) meant the air reservoirs had to be relocated to the roof. They were used in freight and some passenger service.
The air tanks on these look a lot bigger than when they're under the frame. Does anyone know the relative capacity? Is this just an optical illusion - the result of using, perhaps, a longer, skinnier type of tank?
On some engines equipped for passenger use, (such as GP9 style), the tubes went topside to allow a boiler water tank in their original place. There would be a boiler in the short hood and an exhaust stack showing in that hood top. Boxcab E50
