guards were removed from trains on the Piccadilly line in 1987, the Jubilee line in 1988 and the Bakerloo line in 1989. The second order of 1983 stock and completion of the OPO stock conversions allowed the Jubilee line fleet to be made up of 1983 Stock and the Bakerloo line with 1972 Mk II Stock. Some 1972 Mk I stock cars were released to be converted to augment the Victoria line fleet, running in the middle of eight-car trains. The signalling on the Central line needed replacement by the late 1980s. It was decided to bring forward the replacement of the 1962 Stock, due at about the same time as the 1959 Stock running on the Northern line. The signalling was to be replaced with an updated version of the ATO system then in used on the Victoria line, the line traction supply boosted and new trains built. Prototype trains were built with two double and two single doors hung on the outside of the train and electronic traction equipment that gave regenerative and rheostatic braking. The first 8 long car trains of 1992 Stock entered service in 1993. While the necessary signalling works for ATO were in progress, OPO was phased in from 1993–95. ATP was commissioned from 1995–97 and ATO from 1999–2001, with a centralised control centre in West London. A train refurbishment project was launched in July 1991, triggered by a new Fire Safety Code of Practice after the King's Cross fire and to combat graffiti. The short Waterloo & City line had been operated by the main line railways, and the original stock replaced in 1940. This stock was increasingly unreliable, with the line closing for two weeks in March 1989 and again in May 1991. Five 4-car trains of 1992 Stock were ordered by British Rail and these entered service in 1993. London Underground took over the line in 1994. To allow the Jubilee line to be extended to Stratford, a new fleet of trains was ordered in 1992 to replace the 1983 Stock running on the line, as the cost of a new fleet was calculated to be the same as refurbishing the older trains to run with the newer trains. The result was the 1996 Stock, with the first train being delivered in 1996. The Northern line stock needed replacement and the 1995 Stock replaced the mixture of 1959, 1962 and 1972