system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do diesel locomotives use their Diesel engines to produce electric to drive electric motors rather than just use the power from the diesel engine to move the train?
gpt
So, the alternative you're talking about is a direct drive or mechanical drive locomotive. There's a few problems:

- the power being transmitted would require ridiculously large transmissions and gearing which would be breaking all the time. 

- torque. Combustion engines deliver peak torque at a specific designed rpm range. Outside of that range the torque is not optimal... pulling heavy trains requires massive torque. Whereas: the torque provided by an electric motor is constant regardless of RPM. So the ability of the motor to turn the wheels is the same no matter how fast the motor is turning. To deliver a comparable torque curve from a combustion engine you'd need an overly complex and contrived transmission which would, again, be breaking all the time.