The class was created as a locomotive which could haul heavier goods trains at speeds of up to 40 mph.

After formation of the London and North Eastern Railway, the type became known as class K1 and K2 and was adopted as an LNER standard design.

They got the nickname "Ragtimers" because of their lively nature when running at speed and their use of Walschaerts valve gear which was uncommon on the GNR at the time.

They were moved to former Great Eastern and North British lines to supplement existing engines.

Twenty K2s were fitted with Westinghouse pumps so they could pull passenger trains from Liverpool Street on the Colchester and Cambridge lines.