Railway electrification systems using alternating current (AC) at 25 kilovolts (kV) are used worldwide, especially for high-speed rail. It is usually supplied at the standard utility frequency (typically 50 or 60 Hz), which simplifies traction substations. The development of 25 kV AC electrification is closely connected with that of successfully using utility frequency. This electrification is ideal for ra. HistoryMany trial sites were developed at the beginning of the 20th century but developing a main frequency. .
Electric power for 25 kV AC electrification is usually taken directly from the three-phase . At the transmission substation, a step-down is connected across two of the three phases of the high. .
Railway electrification using 25 kV, 50 Hz AC has become an international standard. There are two main standards that define the voltages of the system: • EN 50163:2004+A1:2007 – "Railway application. .
The 2 × 25 kV system is a system which supplies 25 kV power to the trains, but transmits power at 50 kV to reduce energy losses. It should not be confused with the 50 kV syste. .
Systems based on this standard but with some variations have been used. In Japan, this is used on existing railway lines in , , and , of which Hokuriku and Kyush.
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The Brazilian Federal Government has never implemented a National Highway Plan at the same level as developed countries such as the USA, Japan or European countries, which specifically aimed at inter-regional travel, and which should preferably be served by highways.OverviewThe Brazilian Highway System (: Sistema Nacional de Rodovias) is a network of administered by the of Brazil. It is constructed, managed and maintained by the. .
As of 2023 , the system consists of 1,720,700 (1,069,200 ) of roads, of which approximately 213,500 km (132,700 mi) are paved (12.4%), and about 17,000 km (10,563 mi) are , 6,300 km. .
Brazilian are named YY-XXX, where YY is the abbreviation of the which administers the highway and XXX is a number (e.g. ; where SP means that the highway is administered by .
The BR-010 is a radial highway that connects the national capital , to the city of , in the state of . It has the official name of Rodovia Bernardo Sayão (the name of its chief engineer, who died in an acciden.
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