The class was designed by William Martley and introduced in 1869, intended for services between London and Dover.
[1] Martley received authority to build three 0-6-0 shunting locomotives in November 1865, but the company's Longhedge workshops were unable to undertake the order due to other commitments.
By the time they were able to do so, in October 1867, there was a more pressing need for 2-4-0 passenger engines and so the order was changed.
Two further very similar locomotives with larger 6 ft 6 in (1.981 m) driving wheels, making them more suited to passenger duties were constructed between May 1869 and June/September 1870, which were regarded as being of the same class.
[3] These numbers were increased by 459 to become 509–511 following the amalgamation of the LCDR and SER to become the South Eastern and Chatham Railway in 1899.