LNER N2 Class 0-6-2T

The LNER N2 Class was a fleet of 107 0-6-2 condenser-fitted suburban tank steam locomotives developed by Sir Nigel Gresley for the Great Northern Railway in 1920. Built between 1920 and 1929 by the North British Locomotive Company, Yorkshire Engine Company, and the LNER's own Doncaster Works, the class was the standard outer-suburban tank engine on the King's Cross suburban network. One has survived in preservation: 1744 (later 69523), currently at the Great Central Railway.

Gresley became chief mechanical engineer of the GNR in 1911 and continued in the same role for the LNER from 1923. The N2 was a successor to the GNR's older N1 0-6-2T of 1907, which had become inadequate for the heavy King's Cross suburban traffic of the 1920s. The N2 was slightly larger and more powerful, with a superheated boiler, and many engines were fitted with a condenser apparatus visible as a pipe running back from the smokebox along the side tanks, used to recirculate steam in the King's Cross suburban tunnels.

The class was concentrated at King's Cross suburban depots: King's Cross Top Shed (Hornsey), Hatfield, and Hertford North. They worked the heavy King's Cross suburban services through the GN suburbs to Welwyn Garden City, Hatfield, Hertford North, and into the West Riding. The N2 remained the standard suburban tank engine on the GN suburban network until the late 1950s, when the King's Cross suburban electrification began to remove the work.

The preserved 1744 (built by the North British Locomotive Company in 1922) was withdrawn from Hatfield in October 1962 and saved by the Great Northern Society. After successive overhauls it has been in working order at the Great Central Railway, where it carries LNER apple green livery as a tribute to its 1920s and 1940s condition. It is the only surviving GNR or LNER suburban tank from this era.