LNER B2 Class

The LNER B2 Class was a series of rebuilt 4-4-0 express passenger locomotives produced by Edward Thompson, Chief Mechanical Engineer of the LNER from 1941 to 1946, by rebuilding examples of Gresley's earlier B17 Class 4-6-0 'Footballer' express locomotives in 1945 to a two-cylinder configuration with larger cylinders and Walschaerts valve gear, redesignating them as B2 Class. Thompson's rebuilding programme was partly driven by his desire to depart from Gresley's three-cylinder conjugated valve gear, which he considered mechanically unreliable, and to establish his own approach to LNER locomotive design.

The B17 'Footballers' had been designed by Gresley in 1928 for the Great Eastern main line to Cambridge and East Anglia, where their relatively light axle loading suited the lightly-laid ex-GER routes. Thompson's conversion of some examples to B2 standard introduced outside Walschaerts valve gear and a two-cylinder arrangement in place of the three-cylinder Gresley layout, producing a locomotive more consistent with Thompson's own design philosophy but of questionable benefit in service terms over the original B17.

The B2 conversions were a controversial episode in LNER locomotive history: Thompson's relationship with Gresley's legacy was complicated, and several of his rebuilding decisions — including the B2 — were seen by later historians as unnecessary or counterproductive. The rebuilt B2s gave service on East Anglian semi-fast duties under BR. None was preserved.