Photo "blac03a.jpg", 135Kb, greyscale
(1905) The slag track is a 2ft tramway. The slag cars were 3 ton capacity cast iron. They were hauled out to the slag dump by horse. The 1909 Sulphide Descriptive booklet shows such a slag car. Captioned "Tipping Slag. This is a very brilliant spectacle at night." It certainly was. I remember it well. The sight thrilled nighttime train travellers on the Main Northern Line.
A handwheel at either end of the slag car operated a pinion engaging a rack on the outside of the pot. This tipped the pot to pour the slag.