Why Diesel Locomotives Are Actually ELECTRIC

A diesel locomotive doesn't have a transmission. It doesn't connect its engine mechanically to its wheels at all. What it has is a diesel engine driving a generator that produces electricity, which powers traction motors mounted directly on the axles — making every diesel locomotive on the mainline a diesel-electric hybrid that solved the transmission problem by eliminating it entirely. The mechanical transmission capable of handling a 4,000 horsepower diesel engine at the torque loads required to move a 15,000-ton freight train simply doesn't exist. General Motors' Electro-Motive Division understood this when they engineered the FT locomotive in 1939, and the fundamental architecture they built hasn't changed because nothing designed since has handled the physics better.