These are the Flywheel and Reduction Gears showing the 17ft  flywheel with square holes in the rim of the wheel. The holes were to allow the engineman to insert a bar over a fulcrum to turn the wheel if the engine had stopped on top or bottom dead centre. On the same shaft as the flywheel, at the end of the main shaft can be seen a 4ft toothed wheel, this meshes with a 9ft wheel on a second motion shaft where a crank was attached.  This Crank was attached to a  horizontal flat push rod which drove to a Tee Bob at the top of the pit head, and which in turn drove the spears for the pumps at the bottom of the pit 190 yards away.