SR WC 4-6-2 No 34102 Lapford has just left the Marine Station and is opposite the Ferry yard, either shunting stock or heading towards Dover Priory station and Chatham.
The lower building on the left and bigger building on the right are all part of the Customs transit shed, where ferry wagons could be inspected in the dry.

Photo: T.G. Hepburn / Rail Archive Stephenson