Recently competed scratch built GWR Pannier Tank, this is my first 2 1/2in engine for many a year.
The Slaters wheels run in axel boxes that are coil sprung in the horns, the body is made in three sections 1) the tanks boiler and smokebox, 2) the cab, with detailed back head, 3) the bunker.
The engine is RC controlled with a 12v dc sealed 2.3 amhr lead acid battery in the tank space, the charger socket is in the smokebox accessed through opening door, the receiver and ESC are in the bunker.
The motor has an integral gearbox and sits vertically in the firebox space, the drive reaches the rear axle via bevel gears and two idling spur gears. Here are some images of the engine
Mike