They were ordered by Evans and Geach who were contracted to operate the railway's locomotives.
They were designed by Daniel Gooch and based on his Bogie class locomotives built for the Great Western Railway who had previously operated the South Devon Railway.
On 1 February 1876 the South Devon Railway was amalgamated with the Great Western Railway, the locomotives were given numbers by their new owners but continued to carry their names too.
Six similar locomotives were built for the Vale of Neath Railway by Robert Stephenson and Company in 1851.
Some of these could be found working on the South Devon lines after the 1876 amalgamation.