QUOTE: Originally posted by gabe QUOTE: Originally posted by WilRogJr Why do they call them "tunnel" motors? Oh my goodness, a technical question to which I actually know the answer. Move over Randy Stall (joking). They call them tunnel motors because the locomotives were designed to operate more effectively in tunnels. Some railroads, especially the SP, had a considerable amount of long tunnels on their system. The problem with long tunnels is the exhaust from the diesles would reflect in the tunnel and cause temperatures to rise and sometime cause the engine to shut down. This is also the reason the SP developed cab first steam locomotives. Tunnel motors have the intakes closer to the ground where the air is cooler (heat rises) and the intake of cooler air allows them to operate in tunnels for longer periods without over heating. When you see an SD-40-2T look toward the back of the locomotive close to the walkway. On a related aside--the story of UP's 4-8-4 and 4-6-6-4 having a diesle haul them through a tunnel on their way to a steam convention and the diesle overheating is a classic. The two steamers had to steam up in the tunnel and it got so hot the crews nearly melted and all of the smoke alarms in the passenger cars went off. Although, I bet the tunnels got a nice steam cleaning from all of that diesel soot on them. Gabe
QUOTE: Originally posted by WilRogJr Why do they call them "tunnel" motors?
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