The difference with these is some enterprising soul has rather expertly grafted on a Fracmo (UK) continously rated 12V motor, coupled to a 4QD controller board and associated switchgear. The motor is skew-gear driven to the bogie, allowing the bogie to be pushed along and the axles are coupled with a toothed belt.
A weekend with the stick welder, a £20 Halfords car battery and some terminal strip and your children could at last be zooming up and down the garden, having long ago given up on the idea of a ride behind the three cylinder Pacific you started before they were born (I know, been there, done that).
Length 13 inches (each bogie)
Wheels 3 inch diameter
gauge | 5 inch |