LNER Class P1

The LNER's inheritance at the 1923 Grouping included substantial heavy-coal traffic from the East Midlands collieries to London. Coal trains from the New England yard at Peterborough to the Ferme Park yard at Hornsey could be 80–100 wagons long, requiring multiple engines or banking assistance. Sir Nigel Gresley proposed in 1924 a single locomotive that could haul a 100-wagon coal train without assistance, an ambitious goal at the limits of contemporary British heavy-freight engineering.

The P1 design was the answer: a three-cylinder 2-8-2 (Mikado) wheel arrangement combining the wide firebox of the contemporary A1 Pacific (supported by a trailing axle, in classic Pacific style) with eight-coupled drive for adhesion. The boiler, cylinders and motion of the A1 Pacific were re-used; only the wheel arrangement and frame layout were unique to the P1.

The first engine, No. 2393, emerged from Doncaster Works in May 1925. The second, 2394, followed in November 1925. Both engines were sent to New England shed at Peterborough for the heavy coal services. On test the P1s could indeed haul 100-wagon trains over the Peterborough–London route, but in practice this proved impossible to capitalise on operationally, because the LNER's loose-coupled coal wagons could not be marshalled into trains that long without snapping couplings on undulating gradients.

The P1's underuse, running 60-wagon trains because the marshalling yards could not produce 100-wagon trains in practice, meant that two engines, each tractive-effort capable of pulling far more than they were normally given, were a poor return on the considerable investment. No further P1s were built. The design did, however, directly inform Gresley's P2 Class of 1934, a three-cylinder 2-8-2 of similar wheel arrangement but for express passenger work.

The two P1s worked exclusively the Peterborough–London Ferme Park heavy coal traffic throughout their twenty-year careers. The combination of low maximum speeds, slow turn-rounds at terminal yards, and the operational difficulty of forming long enough trains to use the engines' full capability meant that neither engine ever achieved high mileages. Recorded annual mileages in the 1930s were typically 25,000–30,000, about half what an express Pacific would do.

Through the 1930s the class continued in this restricted role. The Second World War brought heavier traffic and the engines were rather better used in 1939–1945, working full coal loadings during the wartime fuel emergency. By the end of the war the P1s were 20 years old, both with relatively low mileages but with worn boilers and accumulated wartime damage.

Both engines were withdrawn in September 1945, among the very first steam locomotives withdrawn by the LNER post-war. They were scrapped at Doncaster Works shortly afterwards. Neither was preserved; the class's narrow operational role and the LNER's post-war motive-power priorities meant that no preservation case could be made for them.

The P1 was a unique LNER design, a three-cylinder Mikado 2-8-2 heavy-freight engine that combined the boiler of the A1 Pacific with eight-coupled drive and a wide firebox supported by a trailing axle. The exceptionally long wheelbase, the high boiler pressed against the cab, and the squat appearance of the eight-coupled wheels combined to give the class an instantly recognisable outline. The two engines were the heaviest steam locomotives ever built in Britain at the time of their construction. They were not named until 1937, when 2393 was named Lord President in honour of the Privy Council's Lord President Sir John Anderson. 2394 remained unnamed throughout its career.

2393, first of class, completed at Doncaster Works in May 1925. Initially unnamed; named Lord President in 1937. Worked the Peterborough–London coal traffic throughout its career. Withdrawn September 1945 with a recorded mileage of approximately 480,000, exceptionally low for a 20-year career, reflecting the class's slow-speed working pattern. Scrapped at Doncaster.

2394, second of class, completed at Doncaster in November 1925 with detail differences from 2393 (different cab fittings and minor running-gear variations). Remained unnamed throughout its career. Withdrawn September 1945. Scrapped at Doncaster.

LNER service (1925–1945): both engines were allocated solely to New England shed at Peterborough for the entirety of their twenty-year working lives. The class worked exclusively the Peterborough–London Ferme Park heavy coal traffic, 80- to 100-wagon trains of unfitted coal wagons, and rarely worked elsewhere on the LNER network. The route between Peterborough and London had been bridge-strengthened to accept their weight, and other sections of the LNER could not handle them.

LNER (1925–1945): standard LNER unlined plain green for goods and freight engines, with simple "L.N.E.R." lettering on the tender. The class never received the apple-green-and-lined finish of the express engines, appropriate for its heavy-freight role.