European Union Prior to 1945 there was no demand for multi-system locomotives in Europe. From the 1950s onwards, the emerging formation of the
European Union, and the consequent increase in the amount of cross border traffic, along with the addition of a
25 kV 50 Hz AC system in France in addition to the older 1.5 kV DC system, gave rise to the need for multi-voltage locomotives. Very high capital costs prevent or hinder the adoption of a standard railway electrification system. At the beginning of the 21st century, railway legislation in Europe (the
First Railway Package and
Second Railway Package, and the creation of a
Trans European Rail Freight Network) liberalised cross border freight traffic, giving rise to a demand for locomotives that could work between
European Union countries with different electrification systems. That created a practically new market for multi-voltage locomotives, such as Bombardier's
TRAXX. However, the increase in the cost of locomotives and maintenance, along with the expense of installing different safety systems for cross-border work, reduced the economic viability of multi-system vehicles versus the use of single-voltage machines or changing locomotives where electrical systems change.
South Africa South Africa has of dual system track, both 3kVDC and 25kVAC.
South Korea at the northern tunnel entrance of Seoul Subway Line 1 Sections of track between
Cheongnyangni station and
Hoegi station, as well as between
Seoul Station and
Namyeong station on
Seoul Subway Line 1, and the section of track (including the flying crossover) between
Namtaeryeong station and
Seonbawi station on
Seoul Subway Line 4, are dual system-equipped with the
subway standard 1500VDC and
mainline railway standard 25kV60HzAC overhead line systems.
United Kingdom could operate from 750VDC
Third rail, 25kVAC
Overhead line and 3kVDC also through Overhead lines. The ability to run on third rail was made redundant with the moving of Eurostar services to
St Pancras railway station in November 2007. Electrification in the UK began in a piecemeal fashion. The earliest main line (as opposed to metro and tramway) systems were divided between low voltage
third rail (commonly about 600VDC) and overhead systems (a variety of voltages, both DC and AC were used). The third rail systems of this period eventually gave rise to the 750VDC system in the southern part of the UK and a separate area with the same system around Merseyside. Cheap loans to stimulate economic development in the 1930s gave rise to the several schemes of 1.5kVDC electrification, mostly completed post war, notably between
Liverpool Street and Shenfield, and the
Woodhead Line. Starting with the
West Coast Main Line electrification in the 1960s, the 25kVAC overhead system was adopted for all subsequent mainline electrification in the UK (except for extensions to other existing systems, mostly on the southern third rail network). In some areas with restricted clearances, particularly in urban areas in east London (converted from 1,500VDC) and on suburban routes around Glasgow, 6.25kV was used. A system known as "Automatic Power Control" was developed to allow trains to automatically switch between the voltages whilst moving. All the driver had to do was shut off power and coast until clear of the neutral section; the system automatically opened the circuit breaker, detected a change in voltage and switched over the transformer to the correct input voltage setting, then closed the circuit breaker. This system proved somewhat unreliable and, with experience, it was found that less clearance was needed for 25kV than had initially been allowed for. This allowed the 6.25kV sections to be converted to 25kV, with the last section, at the London end of the London Tilbury and Southend line, being converted in 1983. Multi-system trains still operate in the United Kingdom. The
British Rail Class 700 electric multiple unit, manufactured by
Siemens Mobility, is used on the
Thameslink network. It runs north to south from , using 25kVAC overhead power north of London, and on to , using 750VDC third-rail power south of London.
United States In the
United States private companies undertook electrification independently, resulting in divergent systems. Thus the
New Haven EP-1 had to support three separate electrification systems: 660 VDC via
third rail, 660 V via
pantograph, and 11 kV 25 HzAC via pantograph; in order to make a journey from the
New York Central Railroad's
Grand Central Terminal in
New York City to its own station in
Stamford, Connecticut. Multi-system operation continues to present day.
New Jersey Transit uses multi-system
ALP-46 and
ALP-45DP locomotives (and also future
Multilevel III Electric Multiple-Units) for its
Midtown Direct service into
New York and
Amtrak uses the multi-system
ACS-64 locomotives and
Acela trainsets on the Northeast Corridor between
Washington DC and
Boston. In both cases, trains run on both newer, 25 kV 60 Hz built or refurbished by their respective agencies since the 1980s and older, 12 kV 25 Hz inherited from the now-defunct
Pennsylvania Railroad. The latter dates to the 1930s, when the Pennsylvania upgraded its electrified network from 650
V DC third rail.
Metro-North Railroad utilizes
M8 electric multiple units on its
New Haven Line, which are capable of using 750VDC Third Rail, 12.5kV 60Hz and 25kV 60Hz overhead electrification. Third rail electrification persists between Grand Central Terminal and
Mount Vernon East, while overhead electrification exists from
Pelham to
New Haven. While traveling between Mount Vernon East and Pelham, trains switch between the third rail and overhead electrification systems without stopping. East of New Haven, M8s operating on
Shore Line East make use of the 25kV 60Hz overhead electrification present. == See also ==