This is a basic motor, you will need to transfer your own worm gear and flywheels to the new motor.
Single & Double Shaft 5-Pole Motor 12v dc For OO Hornby & Bachmann Steam Diesel
Micromotor.eu 1524D Coreless Motor 15mm x 24mm - Double shaft 1-12V
Micromotor.eu 1020D -14000 Coreless Motor 10mmx20mm Double shaft 14000 RPM 1-12V