The Admiralty Military Railway was a line that branched off the main line near Woodlands and was built in the 1930s to serve the Naval Shipyard at Sembawang. Three of the locomotives were 0-6-0Ts built by Hunslet in 1929 and numbered SL18-20. In November 1941 they were transferred to the FMSR as the second Class A, later becoming 331 class before being sold to the Port Of Singapore in 1946. In addition to the metre gauge line there was a standard gauge system and two of the locomotives which operated this system were returned to the UK in 1955. One of these, Hawthorn Leslie 3865 of 1936, an 0-4-0ST named "Singapore", has been preserved.