arrangement with the LSWR and the line was operated from the outset by the S&D. After the 1 January 1923 Grouping ownership of the line passed to the Southern Railway. Working of single line From the late 1870s a number of the single line sections were made double track, to improve handling of the heavy train service, and by 1905 about two-thirds of the main line mileage was double track, and trains could now run throughout from Bath to Bournemouth with reasonable convenience, excepting only the awkward arrangement at Templecombe. Southbound trains calling there (to make connection into the LSWR Exeter main line) had to be hauled back to the S&D junction by a spare engine, then to continue their southward journey; the corresponding evolution in reverse was necessary for northbound trains. This complexity persisted until the final closure of the S&D line. However the remaining single line sections proved a serious delaying factor for the traffic. Safety on single line sections was secured by every train carrying a token for each single line; instruments at the signal boxes were electrically interlocked to ensure that only one token could be out of the instruments for any one section at a time. The tokens had to be handed to the driver of every train by the signalman, and in the case of express trains, this meant slowing to walking pace to secure the handover. Alfred Whitaker, the S&D locomotive engineer, developed a mechanical apparatus; part of this fitted to the locomotive cabside consisted of jaws which caught a loop on a pouch containing the token; the pouch was held at the lineside in a special delivery holder. The token to be given up by the train was correspondingly caught by a catcher fixed at the lineside. This system enabled token exchanges to take place at 40 mph, and considerably accelerated the handling of through trains at single line crossing places. The main line was single from Bath Junction to Midford (inclusive), from Templecombe Junction to Blandford with crossing places at Stalbridge, Sturminster Newton, Shillingstone and Stourpaine, and from Corfe Mullen to both Wimborne Junction and Broadstone Junction. Locomotives and rolling stock Locomotive and rolling stock on the Somerset and Dorset was largely defined by those running the line, the 5 main phases were: Somerset and Dorset, 1863–1875 S&DJR – Midland Railway and LSWR, 1875 – 1923 Post grouping – LMS and