The brushless motors usually require a servo to power them properly so you may be wasting money on one of those. The gear reduction is common on motors used with model trains to ad torque and slow them down some. A model diesel train is meant to start slow and speed up some to make it appear real, they will also incorporate flywheels and other add ons. If you want to really have some fun try a RC helicopter motor with brushes. Have one on a machine that has been passed from artist to artist we nicknamed the widowmaker, noone has actually tattooed a person with it but a few have peeled some bananas at about 4 volts.