PKP class EN57
EN57 is an electric multiple unit used by the Polish railway operator ("PKP"). It was built for suburban and long-distance services. Presently it is used by Przewozy Regionalne (POLREGIO), Szybka Kolej Miejska and Koleje Mazowieckie companies. Out of over 1400 units produced, about 300 still remain in service in Poland, most of them with Przewozy Regionalne. History. Designed for regional transport class EN57 was based on the earlier class EW55 units. EW55 were the first electrical multiple units built in Poland with 100% of domestic components. They were built by Pafawag works in Wrocław. Production started  in 1962 and ended in 1993 with 1412 units produced, most of which are still in operation. This class is believed to have had the longest production period in the world for electric multiple units. The first units had first-class compartments, but units numbered 602 and upwards were produced with only second class. Due to very long production period, the series varies between specific production spans. Units up to number 1113 have corrugated sides and three windscreens, units numbered 1114 to 1825 have flat sides and three windscreens, whilst units from number 1900 up to 1953 have flat sides  and two windscreens, resembling class EW58 units. As the result of several fires and accidents, units numbered 201 to 206 are assembled from surviving cars of previously destroyed units. Since 2006, Przewozy Regionalne have modernized several units with funding from the European Union. The changes affect the appearance of the units, with the ends being redesigned. The interior was also changed. Mechanical and electric devices remain mostly unchanged. Modified units are being renumbered from 2001 upwards. Classes EN71, ED72, and ED73 units were based on class EN57. Szybka Kolej Miejska which operates service in the Tricity area uses these units  and has also modernized them, this being mostly to the interior. Technical data. EN57 is a three-car electric multiple unit with traction motors located in the middle car. The unit has four LK450 motors, each with power of 145 kW. The outer two cars are both driving trailers and do not have motors. Trailers are distinguished with letters "a" and "b", with part "a" including compressor and part "b" including the batteries. Each part of the unit consists of three compartments, divided by corridors. In the trailers only two compartments are for passenger accommodation, while the third was thought  to be luggage compartment. In the motor car, all three compartments are used by passengers. Previously, there were toilets in all parts of the unit, yet due to several fires caused by neighbouring electric devices, the toilets in the motor cars were removed. Class EN57 is capable of multiple unit operation with two or three units, using Scharfenberg couplers to connect units together. Each unit can seat up to 212 passengers. Service in other countries. Three units of class EN57 EMU were exported to Yugoslavia in 1964, where they classified "311-0" (for trailers) and "315-0" (for motor cars ). Another eleven were subsequently rebuilt from class "315-1" with additional trailers. These units later remained in service in Slovenia and Croatia as SŽ 311/315 and HŽ 6011 respectively. As in the time of delivery Władysław Gomułka was the leader of Polish Polish United Workers' Party, those units were nicknamed after him. Modernizations. SPOT and EN57-20XX. In 2006, ZNTK "Mińsk Mazowiecki", Pesa Bydgoszcz and Newag Nowy Sącz begin modernizing 75 EN57 EMUs, financed by European Union funds. The appearance of the end walls, cab driver and interior was changed. The separate service compartments were removed by connecting them with  entrance hallways. The modernized EMU was adapted to the needs of disabled people through the installation of elevators for wheelchairs and bigger toilets. EMUs after modernisation had also installed alarm and 16 cameras. The main spinning transformer was replaced by electronic transformer giving voltage 110 V DC, 230 V AC and 24 V DC. EN57KM. In 2007 SKM Tricity and Koleje Mazowieckie decided to apply the start pulse in some of their EN57's: SKM Trójmiasto: EN57-768, EN57-1089, EN57-1094 i EN57-1116 Koleje Mazowieckie: EN57-1486, EN57-1566, EN57-1567 i EN57-1562 ZNTK "Mińsk Mazowiecki" works  made this modernisations. They too applied microprocessor controlled drive and electrodynamic braking.