;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)
;Drott:Drott Manufacturing Company machine similar to a bulldozer used to level and compact soil
;Drummond:Dugald Drummond, Locomotive Engineer, later Chief Mechanical Engineer (CME) of the London & South Western Railway 1895-1905
;DTCL:Driving Trailer Composite with lavatory