London Underground 1992 Stock & City line, which until 1994 was part of the national railway network, and became their Class 482. When this line passed to London Underground at the start of the process to privatise British Rail on 1 April 1994, these units also passed to London Underground. The vehicles are essentially identical to those used on the Central line; the main difference being that trip-cocks are used for protection instead of ATO/ATP. Transport for London and Metronet closed the Waterloo & City line for five months from April to September 2006 to allow major upgrade work on the tunnels and rolling
Attacks on the London Underground On 9 December, a van bomb partially detonated at the car park of Woodside Park station. No-one was injured but it caused evacuations and disruptions. A device exploded at an underground passageway at South Kensington station on 3 February 1993. On 20 December, a device exploded in a litter bin in Northfields station. On 21 December, coded bomb warnings from the IRA resulted in a paralysed London Underground system, as tens of thousands were evacuated from 100 tube stations during the morning rush hour. In 2005 two groups of Islamist extremists attacked a number of underground lines and bus routes