Changes

;Departmental:Rolling stock used for the railway’s own functions (engineering etc.) rather than for general passenger or goods traffic.

;DMBS:Driving Motor Brake Second

;DMU:Diesel Multiple Unit

;Down:In reference to the direction of travel means away from the major terminus (i.e. towards Bridgnorth on the present day SVR)

;Drummond:Dugald Drummond, Locomotive Engineer, later Chief Mechanical Engineer (CME) of the London & South Western Railway 1895-1905

;Dukedog:A GWR 3200 Class 4-4-0 engine, rebuilt using earlier 'Bulldog' frame and 'Duke' boiler.

;ECS:Empty Coaching Stock

;Super D:An LNWR 0-8-0 goods engine

;SVR:Severn Valley Railway

;TMD:Traction Maintenance Depot, also referred to as Diesel Depot

;Toad:GWR telegraphic code signifying a goods brake van, which became the standard design's nickname

;TOPS:Total Operations Processing System, an American computer system adopted by BR in the late 1960s to number and manage rolling stock.

;TPO:Travelling Post Office

;TUCC:Transport Users Consultative Committee

;Type 1:The British Railways classification for diesel locomotives of up to 1000 bhp