PONTYPOOL GLYN PITS
Vertical Winding House

Above is a corner view from the North West of the winding engine house at Glyn Pits. To within an inch or so, the building is thirty feet square, and thirty-four feet from ground level to the eaves and placed on-site between 1856 and 1865. This picture is too distant to see the fine quality of the masonry, which in this case is dressed stone throughout, but one needs to be close to the building to really appreciate the workmanship, which is a tribute to the men who built it. Seen in this image are the three stone corbels which supported the backstays {bracers} for the headgear. Between the two nearer corbels, and over the bricked-up window on the right, can be seen the slot in the wall - now plastered with grease thrown from the rope - through which the upcast rope left the building. while the other rope exited the building through a slot in the roof. It was through the nearest of the two largest red bricked up windows { Breached } that the engine driver would have viewed the pit-head, or 'Bank' when winding.
This simple line animation shows live steam - coloured blue - entering the cylinder on the right of the drawing, forcing the piston up, and then utilizing valves, forcing the piston back down. Exhaust steam - coloured yellow - is exhausted to the left of the drawing. The piston rod is joined by a connecting rod to a crankshaft with the movement being stabilized by a crosshead and guides. The crank is connected to a brake wheel and the two rope wheels, with the red upcast rope exiting through the slot between the corbels of the house, while the blue, downcast rope exits through a hole in the roof. Both shafts at the Glyn were 190 yards deep, with coal and men being wound from 186 yards.