British Rail Class 484

The British Rail Class 484 is a class of electric multiple unit which is to be built by rolling stock manufacturer Vivarail for the Island Line on the Isle of Wight. The units will be converted from London Underground D78 Stock, originally manufactured in the late 1970s and early 1980s by Metro-Cammell.

Five units are to be converted for Island Line to replace the Class 483 sets, with the first due to be delivered for testing in 2020.

History
The Island Line, an 8+1/2 mi long rail route on the Isle of Wight between Ryde and Shanklin, has, since 1966, been limited in the type of rolling stock that can be operated by the clearance level in the Ryde Tunnel between Ryde Esplanade and Ryde St John's Road. Since 1989, rail services have been run using units, which, prior to this, had been used on the London Underground's Northern line. However, these units were first introduced on the Underground in 1938 and, by 2019, were more than eighty years old. This made them increasingly difficult to maintain, with the original fleet of eight eventually reduced to four in service, with another two retained as spares donors. As a consequence, replacement of the rolling stock became an urgent priority - this requirement was eventually linked with a wider need to invest in improvements in the line itself, and saw suggestions that it might be converted to a light rail operation, or even a bus rapid transit route. However, in 2019, it was announced that the existing third rail operation would be retained, with a total of £26m invested to make improvements. A significant proportion of this would be used on the procurement of a fleet of new trains, which it was announced would be sourced from Vivarail's D-Train platform.

Trains
The Class 484 units will be two-car trains built using the existing bodyshells and bogies of former London Underground D78 stock units modified for use on the National Rail network. These will have similar features to the trains from the same family, with wi-fi, power sockets and CCTV. The D78 Stock is similar in terms of height to other National Rail rolling stock in Great Britain, although gauging trials took place in the 1960s to determine whether units were suitable for use on the route. The first of the total of five units is due to be delivered for testing in the summer of 2020.