Until 1880 the Great Eastern had taken over the operation on the lines of the LT&SR and thus also provided the locomotives. When this agreement expired, Thomas Whitelegg began developing a new passenger tank locomotive for the suburban trains. He enjoyed the help of William Adams, who was the former superintendent of GER and was now with the London & South Western.

The result was based on the LSWR class 46 tank locomotive with a 4-4-0T wheel arrangement. The same driving wheel diameter was used and a trailing axle was added, giving a 4-4-2T wheel arrangement for the first time on a British tank locomotive. Although the trailing axle was mounted directly in the frame, the axle bearings were radially adjustable and thus reduced the rigid wheelbase of the locomotive. As with the class 46, the cylinders were on the outside.

The first production lot was 18 locomotives, delivered by Sharp, Stewart & Co. in 1880 and 1881. The same company supplied twelve more in 1885. It was not until 1895 that Nasmyth, Wilson & Co. supplied another six. From 1902 at least four were equipped with a condensation device, while some received a roof specially adapted to tunnels. All locomotives not only came to the Midland Railway in 1912, but also to the LMS in 1923. Their decommissioning took place between 1929 and 1936.