I assume you're referring to a diesel-electric locomotive. It'sbasically the same as your every day car engine, except your carmight have 4 cylinders the size of the width of your hand, while ina locomotive has 16 cylinders the size of the width of both yourhands together. So this is what happens: Fuel is injected into theengine the same way as your car. As energy is produced it goes tothe traction motors located in the trucks (wheel base). Thetraction motors then turn the diesel power into electric power,hence the name 'diesel-electric.' The electric energy then turnsthe wheels. The throttle is the same thing as the gas pedal on yourcar. The throttle is marked with 8 notches and the higher thenotch, the more power is put into the wheels. I hope this answeredyour question!