The unique SECR S 0-6-0ST No 1685 which was converted from a Wainwright Class C 0-6-0 in 1917 for heavy shunting duties at Richborough Port.
Given that it got its four-digit number in 1934 this photo is no earlier than that. This engine was allocated to Bricklayers Arms for shunting there from 1919 until diesels appeared in '51 (Bradley - Loco history of the SECR) and it is outside one of the loco sheds with the goods shed behind. I think the freshly repainted Stephenson Clarke wagon in the background is just as interesting.

Photo: R.S. Clark / Rail Archive Stephenson