The Engines work as follows:-
Steam is introduced into the cylinder ( 1 ), from the boiler by hand levers, and this forces a piston to move up and down in the vertical cylinder. A rod (19 ) attached to the piston passes through the top of the cylinder and is linked to one end of the massive iron beam (18 ), pivoted about its centre. The motion of the piston causes the beam to rock in a "See-Saw" fashion.
The rod ( 23 ) fixed to the opposite end of the beam is attached to the top of the pump rod in the basement. This rod extends vertically through the centre of a 21" diameter pipe that goes down 200' to the bottom of the well. These pump rods with valves attached both to the bottom of the rod and to the bottom of the pipe, when moved up and down, lift large quantities of water to the surface. The well is of oval section, 18' x 7' and there is a pipe and pump rod for each engine.
A further rod ( 20 ), attached to the beam and situated in front of each engine cylinder, operated a second pump, that forces the water already lifted to the surface, up to the covered reservoir from where it flows into Nottingham's water supply.
A connecting rod ( 22 ) is attached to a large flywheel ( 24 ) by a crank. This maintains an even motion to the engine, so that once it has reached a speed of 11 1/2 rpm, it will continue to operate without hand assistance. The speed is controlled by a Watt's Patent Governor, linked by rods with the steam supply to the engine.
In addition other rods are connected to an air pump ( 25 ) which removes condensed steam and air from the condenser ( 6 ) situated beneath the floor. There is a boiler feed pump ( 16 ) and rod ( 26 ) that replaces water as required in the boilers, while any surplus flows back to the cooling pond.