the embankment to the edge of Tide Cove. Nobody was injured. The same locomotive involved in the 1923 incident was involved in a more serious derailment on 20 April 1931. Owing to heavy rains, an embankment at Ma Liu Shui south of today's University station was weakened. It collapsed as a Kowloon-bound train passed over it at about 17:10, causing the locomotive and four carriages to crash and pile atop one another. There were 12 deaths and eight serious injuries. On 12 November 1955, a fatal accident occurred at Mile 17, the site of a private military level crossing. A speeding passenger train struck a British military "Comet" tank at the crossing. A new diesel electric locomotive, the Sir Alexander (now exhibited in the Hong Kong Railway Museum), derailed. Various other carriages were severely damaged. The train guard and a member of the tank crew were killed. At 15:00 on 18 December 1980, a contractor building Mong Kok (now Mong Kok East) station accidentally severed signalling cables, disabling the automatic signalling system. At this time, the railway had been only partly doubled-tracked, and still made use of the old single-track Beacon Hill Tunnel. Later in the day, two trains were inadvertently put on a head-on collision course just south of the tunnel. At 18:40, a Lo Wu-bound train carrying about 1,500 passengers reached the point where the double-tracked section of the railway ended ahead of the tunnel, near Yau Yat Chuen. A safety device, a trap point, prevented the collision by forcing the train to derail, causing minor injuries to some passengers. A minute later, a southbound train came to a screeching halt at the accident site. A KCR spokesman blamed "a misunderstanding in a telephone communication". On 25 November 1984, a train derailed between Sheung Shui and Lo Wu stations. The incident occurred when the driver, meaning to back the train up to Sheung Shui station, failed to follow a speed/stop signal while the train was exceeding the speed limit. The train was being driven from the rear cabin, with the driver relying on signals from the train guard who was in the front carriage. The train sped past a danger signal onto a siding at 30 km/h, rather than shunting onto the main line at 10 km/h as it was meant to. It crashed into a concrete buffer at the end of the siding, with the first two