and RegioEkspres trains share the same fare for 2nd class (meaning you can board an RE train with an IR ticket and vice versa). With the exception of the Szczecin-Warsaw and Poznań-Warsaw RegioEkspres trains, there is no reservation required in any of Przewozy Regionalne's trains. Until December 1, 2008, the company also used to run over 300 interregional and international fast trains (), but per the government's decision, all its interregional and international fast train services were transferred back to its then-sister company, PKP Intercity S.A. and rebranded to 'Tanie Linie Kolejowe' (Cheap Railway Lines), this was then itself renamed in 2010 to 'Twoje Linie Kolejowe' (Your Railway Lines). Przewozy Regionalne trains are currently operated under the following brands: 2015 Regio InterRegio RegioExpress InterRegioBus - BUS Power supply Electric train traction of Polish State Railway started in 1936 in Warsaw area and is performed since the beginning with 3 kV DC. On January 1, 2011, 11481 kilometres were electrified by a total length of 19276 kilometres. All used power is taken from the public grid and rectified in substations. Most substations are fed with voltages between 15 and 30 kV. Where lines have heavy traffic and higher speed, the substations are fed from the 110 kV grid. The switchyard of substations fed from voltages below 30 kV is indoors, outdoor switchgear is used at 110 kV. The distance between substations is between 15 and 28 kilometres. For reliability of supply, substations are usually fed by at least two powerlines. Each substation normally feeds two segments of the overhead wire, which are separated by a switch. As is common with DC systems, the negative pole is grounded. Halfway between two substations, there is a switch, which can be used to connect the overhead wires together. At some lines, a three-phase AC line operated with 6 kV, 15 kV or 20 kV runs parallel to the railway line, either on the poles of the overhead wire or on separate poles. It is used for power supply of signals, level crossing equipment and other devices requiring electric power used for the rail. This line can be also used for emergency power supply of substations. Other PKP subsidiary companies Polskie Linie Kolejowe The PKP Group company responsible for maintenance of rail tracks, conducting trains across the country, scheduling train timetables, and management of railway property, such as lines and stations. PKP Energetyka A company