If main line railways are operated with direct current, therefore, they generally use a higher voltage of 1,500 or 3,000 V compared to trams and electric narrow-gauge railways with their regional networks (600 to 1,200 V).
People Also Ask
For mainline and high-speed railways with long distances between power supply substations, overhead line electrification is often the preferred choice. The ability to transmit high-voltage power efficiently and support longer trains makes it a suitable option for these applications.
Railway electrification using alternating current (AC) at 15 kilovolts (kV) and 16.7 hertz (Hz) are used on transport railways in Germany, Austria, Switzerland, Sweden, and Norway.
As you know 25kV is globally accepted voltage level for electric locomotives. Reasons to choose 25 KV instead of 240/415V is that for less voltage like 240V or 415V, flowing current increase to dangerously high value and counductor/Line could be burnt out.
High voltage has higher potential energy than low voltage. Low voltage has lower potential energy than high voltage. High voltage is typically used to power large devices, while low voltage is usually used to power smaller devices.
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.
Electric trains generally draw power from AC overhead lines. Some DC lines do exist, but they are getting replaced by AC lines. Motors used (traction motors) are generally DC motors.