away, to a railway feeder station located beside the tracks. Since only two phases of the high-voltage supply are used, phase imbalance is corrected by connecting each feeder station to a different combination of phases. To avoid the train pantograph bridging together two feeder stations which may be out-of-phase with each other, neutral sections are provided between sections fed from different feeder stations. SVCs are used for load balancing and voltage control. In some cases dedicated single-phase AC power lines were built to substations with single phase AC transformers. Such lines were built to supply the French TGV. Standardisation Railway electrification using , AC has become an international standard. There are two main standards that define the voltages of the system: EN50163:2004+A1:2007 - "Railway applications. Supply voltages of traction systems" IEC60850 - "Railway Applications. Supply voltages of traction systems" The permissible range of voltages allowed are as stated in the above standards and take into account the number of trains drawing current and their distance from the substation. This system is now part of the European Union's Trans-European railway interoperability standards (1996/48/EC "Interoperability of the Trans-European high-speed rail system" and 2001/16/EC "Interoperability of the Trans-European Conventional rail system"). Variations Systems based on this standard but with some variations have been used. 25 kV AC at 60 Hz In countries where is the normal grid power frequency, at is used for the railway electrification. In Canada on the Deux-Montagnes line of the Montreal Metropolitan transportation Agency. In Japan on the Tokaido, Sanyo and Kyushu Shinkansen lines (using gauge). In South Korea on the Korail network. In Taiwan on the Taiwan High Speed Rail line (using gauge) and on Taiwan Railway Administration's electrified lines (using gauge). In the United States on newer electrified portions of the Northeast Corridor (i.e. the New Haven-Boston segment) intercity passenger lines, New Jersey Transit commuter lines, Denver RTD Commuter Rail and select isolated short lines. In the San Francisco Bay Area, Caltrain is currently undergoing an electrification project, to be completed in the mid-2020s. 20 kV AC at 50 or 60 Hz In Japan, this is used on existing railway lines in Tohoku Region, Hokuriku Region, Hokkaido and Kyushu, of which Hokuriku and Kyushu are at 60Hz. 12.5 kV AC at 60 Hz Some lines in the United States have been electrified at or converted from to . Use of allows direct supply from the 60Hz utility