The British Rail Class 305 was an alternating current (AC) electric multiple unit (EMU). Under the pre-1973 British Rail numbering system, the class was known as AM5. When TOPS was introduced, the class became Class 305. Subclasses Class 305 had three subclasses: 305/1 3-car units, standard class accommodation only, 52 units built in 1960 305/2 4-car units, first and standard class accommodation, 19 units built in 1959 305/3 4-car units, first and standard class accommodation, 8 units converted from 305/1 in 1988 by adding a TC from units 305/9 3-car unit, non-passenger departmental conversion, converted 1984 Operations 305/1 units were generally deployed on inner suburban services on the Lea Valley lines out of London Liverpool Street to Chingford, Enfield Town and Hertford East. They mainly worked the Chingford and Enfield branches, where their average scheduled speed was . However, they were also used on the Great Eastern lines out of London Liverpool Street and occasionally worked out of their ‘normal’ operating area when coupled to a 305/2 unit or any of the compatible EMUs in use at the time. These units were distinguished by their lower backed seating. 305/1 units were replaced from 1980 onwards by British Rail Class 315 units. They were not generally used elsewhere, but a small number of units, are believed to have operated around Manchester for a brief period in the mid 1990s. All examples of the subclass were scrapped. 305/2 units were generally deployed on outer suburban services on the Lea Valley Line out of London Liverpool Street to Bishops Stortford (the extent of electrification until 1987), where their average scheduled speed was . Like the 305/1 units, they could occasionally be seen on other services out of Liverpool Street and were sometimes coupled to other compatible EMUs for multiple workingScotRail . One unit was converted in 1984 for use as a mobile classroom in connection with the East Coast Main Line electrification project, becoming unit 305935, painted in InterCity livery. One of the driving vehicles contained blue asbestos and was subsequently replaced with a driving vehicle from a withdrawn Class 302 set, forming a hybrid set but retaining the same unit number (305935). The unit was later used in East Anglia as part of the Great Eastern electrification and was deployed at Ipswich, Harwich and Cambridge. The 305/2s were refurbished in the mid-late 1980s. As with the 308s, this involved moving first class