By Anupum Pant
Diesel locomotives have diesel engines, of course. But the overlooked fact about these locomotives is that the diesel engines in them aren’t exactly there to power the wheels. Instead, the diesel engine turns an electric generator with a constant speed and the electricity produced is used to power traction motors. So, in reality these locomotives have hybrid engines, not exactly diesel.
The reason for this is pretty straight forward. The massive diesel engines of a diesel locomotives can only turn at slow RPM. So slow that about 1000 RPM is the red line for these engines. That means to keep producing the maximum torque and horsepower and reach high speeds, in a hypothetical engine like that one, which had to turn wheels directly, there’d have to be about 30+ gears.
30+ gears would make the gearbox massive. And something that could take thousands of units of horsepower would make it a very inefficient one. Hence, hybrid engines…