The North Eastern Railway classes P through P3 comprised a total of 355 0-6-0 wheel arrangement locomotives that were produced between 1894 and 1923. They were created by William Worsdell, who had been employed as chief engineer at the Great Northern since 1890 and were primarily intended as mineral engines, i.e. for the transport of heavy, slow coal and ore trains. From 1923, the individual variants were classified by the LNER in classes J24 to J27 when the railway companies were grouped.
It all started with the P class, which was built a total of 70 times in the Great Northern workshops in Gateshead and Darlington between 1894 and 1898. The cylinders were 18 inches in diameter and 24 inches in stroke and operated at a steam pressure of 160 psi. Between 1914 and 1920, 20 locomotives were converted to superheated steam, the cylinder diameter was increased by half an inch and the slide valves were replaced with piston valves. In 1948, when British Railways was founded, a total of 34 units could be taken over, but they soon disappeared.
British Railways P3 No. 65804 brings a Brake Van back to the coal mine in May 1965
Ben Brooksbank / Engine & brakevan at Winning, near North Blyth 
Immediately following the production of the P class, the P1 class followed, in which the cylinders now had a diameter of 18.25 inches and a stroke of 26 inches. In addition, the boiler barrel and the firebox were lengthened and the wheelbase adjusted accordingly. The 120 pieces were made again in Gateshead and Darlington, with Gateshead again taking over the main part. For the last 20 pieces, the cylinder diameter was increased to 18.5 inches. During the Second World War, the LNER, which meanwhile operated the locomotives as class J25, lent 40 units to the Great Western. The British Railways took over 76 units in 1948 and retired them between 1950 and 1953.
In the years 1904 and 1905, a total of 50 examples of the P2 followed, which were again manufactured in the same works. They had the same cylinder dimensions as the last series of P1s and had a significantly larger boiler, which also now operated at a pressure of 200 psi. This not only increased the starting tractive effort and steaming capacity, but also resulted in an adhesive weight that was more than five tons higher. British Railways took over the entire stock and retired it between 1952 and 1966.
Between 1906 and 1909, initially 75 pieces of the P3 followed, of which only some were built in the company's own workshops in Darlington. The rest was divided among several commercial manufacturers. The biggest change was the higher-mounted boiler, which featured a deeper firebox with a less steep grate. Twelve years after the end of production, two more series totaling 35 pieces were commissioned. These were factory-fitted with a Schmidt-type superheater. In 1948, British Railways also took over all the P3 units. Their decommissioning began in 1959 and was completed in 1967.