Merseyrail in the context of "List of railway electrification systems"

The Budapest Metro (Hungarian: Budapesti metró, pronounced [ˈbudɒpɛʃti ˈmɛtroː]) is the rapid transit system of the Hungarian capital Budapest. Opened in 1896, it is the world's second oldest electrified underground railway after the City and South London Railway (1890), and the third oldest underground railway with multiple stations after the originally steam-powered Metropolitan Railway (1863), both now part of the London Underground, and the Mersey Railway, now part of Merseyrail in Liverpool (1886). Between 1970 and 1990 the metro was extended with metro line M2 and M3. Metro line M4 was completed in 2014. Since 2014 the length of the entire metro system is 39.4 kilometers and it has 52 stations.

Budapest's first line, Line 1, was completed in 1896. The M1 line became an IEEE Milestone due to the radically new innovations in its era: "Among the railway's innovative elements were bidirectional tram cars; electric lighting in the subway stations and tram cars; and an overhead wire structure instead of a third-rail system for power." In 2002, the M1 line was listed as a UNESCO World Heritage Site.

The Mersey Railway was the passenger railway connecting the communities of Liverpool and Birkenhead, England. It is currently a part of the Merseyrail network. It was extended further into the Wirral Peninsula, which lies on the opposite bank of the River Mersey to Liverpool. Both sides of the river were connected via the Mersey Railway Tunnel. The railway opened in 1886 with four stations using steam locomotives hauling unheated wooden carriages; in the next six years the line was extended with the opening of three more stations. Using the first tunnel under the Mersey, the line is the world's oldest underground railway outside London.

Because the steam locomotives created a polluted atmosphere in the tunnel despite the forced ventilation system, many passengers reverted back to using the river ferries making the railway bankrupt by 1900. Recovery came after the railway adopted electric traction in 1903. The Mersey Railway remained independent after the railway grouping of 1923, although it became closely integrated with the electric train services operated by the London, Midland and Scottish Railway over the former Wirral Railway routes after 1938. The Mersey Railway was nationalised, along with most other British railway companies, in 1948.

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 DC third 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.

According to Network Rail, as at 2003, 64% of the electrified network used the 25 kV AC overhead system, and 36% used the 660/750 V DC third-rail system.