until the late 1990s, when they were again retired. Car 8 was returned to Southend to join the Southend Pier Museum collection, and car 9 is on display at the South Downs Heritage Centre at Hassocks. 20th Century In 1909 a further four trailer cars were purchased to form four trains of five cars each. The motor cars proved to be underpowered for this load and, in 1910, each motor car was refitted with twin BTH motors. In 1911 the conductor rail was replaced with 45lb/yard steel rail, similar to the running rails, with new pickups, made of cast iron, being fitted to the motor cars. In 1914, another eight cars were purchased and the trains made up to seven cars each. In 1919, the original track, now twenty years old, needed replacement, so new running and conductor rails were laid throughout the pier. In 1923, experimental magnetic brakes were fitted to one train set. The experiment was evidently not a success as they were discarded after about a year. At the same time, new wheels with Bessemer steel tyres were fitted to all the cars. The year 1928 saw the extension of the midway loop by a further and new loops were constructed extending from the North (shore) and South (pier head) stations. The following year these loops were joined up to form a double track railway 93 chains, () long, along the length of the pier. The track came out of cover at pile 18, the two signal cabins were at piles 47/48 and 179/180, and the south station was at piles 217 to 225. At some stage, a workshop was built along the west side of the shore station to handle routine maintenance. During the Second World War the pier was closed to visitors. It was taken over by the Royal Navy on 9 September 1939, and renamed HMS Leigh, and was used as an assembly point for convoys with anti-aircraft guns on the pier head. It was also the main shipping control point for the Thames Estuary. The trains were used to supply the guns with ammunition and ferry casualties ashore from the ships. Masters of passing merchant ships used to complain the trains set off the acoustic aircraft early warning devices fitted to their vessels. By 1949 the original rolling stock was approaching 60 years old and so it was decided to replace it. New