LNER Class A2

LNER A2 class
A2 class 2400 on trial at King's Cross Station in June 1923
Type and origin Power type Steam Designer Vincent Raven Builder NER/LNER Darlington Works Build date 1922 (2), 1924 (3) Total produced 5
Specifications Configuration: ​  • Whyte 4-6-2  • UIC 2′C1′ h3 Gauge 4 ft 8 1⁄2 in (1,435 mm) Leading dia. 37.25 in (0.946 m) Driver dia. 80 in (2.032 m) Trailing dia. 45.25 in (1.149 m) Fuel type Coal Fuel capacity 5.5 long tons (5.6 t) Water cap 4,125 imp gal (18,750 l) Boiler pressure 200 psi (1.38 MPa) (most), 180 psi (1.24 MPa) (2404) Cylinders Three Cylinder size 19 in × 26 in (483 mm × 660 mm) Valve gear Stephenson Valve type 8 3⁄4-inch (220 mm) piston valves
Performance figures Tractive effort 29,918 lbf (133.08 kN) (most), 26,926 lbf (119.77 kN) (2404)
Career Operators North Eastern Railway London and North Eastern Railway Numbers 2400–2404 Withdrawn 1936–1937 Disposition All scrapped

The first London and North Eastern Railway (LNER) Class A2 was a class of 4-6-2 steam locomotive designed by Vincent Raven for the North Eastern Railway (as NER class 4.6.2). Two were built by the NER in 1922 before the grouping and another three by the LNER in 1924. Their LNER numbers were 2400–2404. All five locomotives were named by the LNER.

The NER was the largest and most prosperous of the railway companies that would make up the LNER from 1923 and provided the general manager of the new railway company. However the chief mechanical engineer of the NER, Sir Vincent Raven was at retirement age and the new post was eventually offered to Nigel Gresley of the Great Northern Railway. He had introduced a powerful new A1 Class pacific in April 1922, and Raven was anxious to show that the NER could keep up with the race for increased power. Raven's rival design was authorised at the same time as the introduction of the A1 class publicised in the railway press in July 1922 although the first two examples did not appear from Darlington Railway Works until late December, and only one of them ran before the beginnings of the LNER.

The new class was an enlarged version of the successful Z class Atlantics (later LNER C7 class) with a larger boiler, larger cylinders and wide firebox. The boiler pressure was also increased to 200 psi (1.38 MPa). They shared with the Gresley K3 class the record for the largest diameter boiler in Britain, at 6 ft (1.83 m). Also, because of the great length of their parallel boilers, the locomotives earned the nickname 'Skittle-alleys'.