In the UK we had 'Mechanical Horses' from 1934 to the late '60's, which were owned both by the railway companies and also by many industries.
This is a model (converted white metal kit) of the original 3 Ton version, which had an 1100cc petrol engine.
The model is radio controlled, 1:43, and will run for two exhibition days between charges (650mAh battery)
The servo is a 1.7g type, and is situated where the engine would be (in the cab with a cowl over it).
You can just see the RX tucked in in front of it, and the wiring just gets shortened, pinned and glued as far away as possible.
The gearmotor is miniscule, but still powerful at 6mm x 8mm x 23mm, and is tucked under the chassis.