In the early 1960s (1960 to 1963, to be exact) a small fleet of 9F 2-10-0 locomotives were transferred to the line for the duration of the summer timetable period (roughly June to September) to work on the heaviest passenger trains. They included (in 1962) No. 92220 "Evening Star", the last steam engine to be built by British Railways. These locomotives proved ideal for the S&D, delivering considerable power, good steaming, and high adhesion. These heavy freight locomotives had relatively small wheels, and were not designed to run with passenger trains, but with the "Pines Express" they were easily able to reach, and perhaps exceed, the 70 mph line speed limit on the better, downhill parts of the route. After a review of the velocities of the reciprocating masses and coupling rods, a 60 mph maximum speed was urgently imposed.