943 were constructed, making them the largest single class of steam locomotives built in the United Kingdom.

The "DX" goods engine was the first original design produced by Ramsbottom, shortly after becoming Locomotive Superintendent of the Northern Division.

It was painted in the same dark green livery as used by Ramsbottom's predecessor, Francis Trevithick, but edged with a single black line.

They were virtually identical in specification, except for slightly larger 5 ft 6 in (1.676 m) driving wheels and smaller 16-inch (410 mm) diameter cylinders.

[1] This alarmed independent locomotive manufacturers, who sought an injunction to stop the practice;[7] it was granted on 16 December 1875.

[12][13] From April 1881, Webb rebuilt 500 examples with a new 150 psi boiler and vacuum brakes for working passenger trains.

The chassis of a withdrawn DX Goods locomotive was repurposed as a stationary engine on the Sheep Pasture Incline of the Cromford and High Peak Railway in February 1884 but was replaced by an electric winch in 1964.