London–Aylesbury line Aylesbury and by platform extensions up to Stoke Mandeville. In 1961 LT withdrew the Metropolitan line from Aylesbury and since then it goes only as far as Amersham. Following the end of steam-hauled Metropolitan line trains in 1961 the service was provided by British Rail Class 115 diesel multiple units until 1992 (which were then replaced by the line's current rolling stock) - along with Metropolitan line electric multiple units south of Amersham. Responsibility for the line north of Amersham was transferred from London Transport to British Railways on 11 September 1961; London Underground signage at the stations on this
Suicide on the London Underground rushes on overhead". A study of 58 cases showed that the presence of a suicide pit halved the number of deaths. Another safety mechanism are platform edge doors (PEDs), which separate the train from the passengers. These are installed exclusively at the below-ground stations of the Jubilee Line Extension. PEDs are expensive to install and can fail to open, adding a potential reliability problem to train services. Alison Wertheimer wrote in 2001 that there were 100–150 suicides annually on the Underground. The annual number of suicides in the 1940s was 25, increasing to 100 by the 1980s, which, according to