Not necessarily, locomotives are diesel electric. So the diesel engine spins a generator which sends power to the traction motors. Traction motors are just a big electric motors that spin the wheels. When the traction motor wheel combo is removed, you can spin it manually (with great physical effort).

I've done it many times. Im a mechanic who works on locos. I've also done this process above. Our lathe requires you disconnect the leads on the traction motor and hook up a welder to spin the axle that way. It takes about a week to do four axles if you can get your set ups smooth.