Beyond may be seen the upright cylinder, with the valve chests and valve
mechanism in front. Above the cylinder is the piston rod, and above this,
the parallel motion linkage which guides the upper end of the piston rod
in a straight line whilst the end of the beam swings in an arc.
The twin winding drums outside the house are aligned with the former wooden headframe over the shaft, being mounted on the crankshaft which passes through an opening in the west wall. The use of twin drums enables one skip to be lowered whilst the full one is being hoisted.
The 12.2 ft diameter flywheel having a weight of some 8600 lb. is acted upon when the engine is at rest by large wooden brakes brought into operation by a handwheel at the driver's position.
The double-acting cylinder has a 27 inch bore and the piston a 4 ft stroke. A regulator valve, operated by the driver, controls the quantity of steam to the engine. The two inlet and two exhaust steam valves are of the efficient Cornish double beat type, and are operated through a rod and shaft mechanism by one of two eccentrics on the crank shaft; connection to one eccentric provides turning in one direction and to the other provides turning in the other direction.
The exhaust steam enters a condenser below the floor where contact with
cold water creates a vacuum thereby increasing the engine power and efficiency.
A vertical rod from the beam works a pump which removes water and uncondensed
vapour from the condenser.
The boiler, of the Cornish single flue type, is located in the boiler house alongside the engine house. Its working pressure would have been about 30 pounds per square inch.
Totally enclosing the whim in a house was probably due to the exposed nature of the site, open to the full fury of Atlantic gales and sea spray. Inside the house, the most prominent features as one enters are the crankshaft and flywheel, the overhead 17.4 ft rocking beam weighing some 4500 lb. and supported on a massive timber spanning the house. A sweep rod links one end of the beam to the crank.