What sort of motor is best for continous high torque applications?

That's the motor that drives the sanding drum, it doesn't specify the motor that drives the belt that drives the workpiece through the machine. That's the one I was referring too, I should have made that clearer. It looks like a fairly beefy little motor.

You may be able to tell me what it is from the info from the manual for that motor:

Motor (TEFC) .................................................................................................. 1-3/4HP, 1Ph, 115V only

It does a max of 10 feet per minute so its not turning really fast.