NER Class P
The NER Class P was a class of 0-6-0 steam locomotives of the North Eastern Railway. They were designed by Wilson Worsdell for mineral traffic.
Modifications
As built the locomotives had slide valves, but 20 were fitted with piston valves and superheaters between 1914 and 1920. The cylinder bore was increased by half an inch at the same time.In the infobox 'ns' denotes non-superheated and 'su' denotes superheated. Some locomotives later had their superheaters removed but the piston valves were retained.