One wheel on each set has a traction tyre. As found on service sheets 301 & 323.
Hornby Spoked Drive Unit Driving Wheel x 2 (S4355)
Hornby 00 Class 31 Motor Drive Unit and Pads With Drive Shaft X9317 high detail
Hornby X9922 Power Car Drive Unit Wheels Axles Drive Shaft For Class 43 HST NEW
