Acton Central station is a changover point from 750VDC third rail, to 25kVAC overhead electrification, on the North London Line
Railway electrification in Great Britain began in the late 19th century. A range of voltages has been used, employing both overhead lines and conductor rails. The two most common systems are 25 kV AC using overhead lines, and the 750 V DCthird rail system used in Southeast England and on Merseyrail. As of October 2023, 6,065 kilometres (3,769 mi) (38%) of the British rail network was electrified.[1]
According to Network Rail, as at 2003, 64% of the electrified network used the 25kVAC overhead system, and 36% used the 660/750VDC third-rail system.[2]
The electrified network is set to expand over the coming years, as 25kV electrification is extended to currently unelectrified lines such as the Midland Main Line, as well as lines in the North of England as part of the Northern Hub.[3]
^Network Rail, 2003 Technical Plan, Chapter 11 "Network Capability", page 7 "Electrification". "Approximately 40% of the rail network is currently equipped with electrification." From page 1, total network is 30764 km, 7587 km of 25 kV AC, 4285 km of 650/750 V DC and 28 km of 1500 V DC. Excludes CTRL, LUL, Old Danby test track, bulk of Tyne and Wear Metro, etc. NB it does not state what method of counting length of network is used - i.e. sidings, loops, double track etc. produce different numbers. The UIC statistics that are used in the chart showing electrification in Europe is based solely on line length. Thus, on this count, 11,900km (38.7%) is electrified. Of the electrified network, 63.8% is 25kV AC, 36.0% is 650/750V DC and 0.2% is 1,500V DC.