[dtegart]

One of the major reasons for these trucks and the locomotives having electric motors, is that maximum torque is available from 0 rpm in an electric motor. A diesel or petrol engine will max torque further up it's power band. This means these large machines are much easier to get moving.

[mcculley]

Likewise for tugboats. Reversing the direction of a propeller is quicker and causes much less wear than with a transmission.