PKP class EP08
Encyclopedia
PKP class EP08 is the name for a Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 electric locomotive
Electric locomotive
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or an on-board energy storage device...

 used by the Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 railway operator Polskie Koleje Państwowe
Polskie Koleje Panstwowe
is the dominant railway operator in Poland.The company was founded when the former state-owned operator was divided into several units based on the requirements laid down by the European Union...

(PKP), produced between 1972 and 1976 in Pafawag
Pafawag
Pafawag is a Polish locomotive manufacturer based in Wrocław. The company became part of Adtranz in 1997 as Adtranz Pafawag, and in 2001 part of Bombardier Transportation...

, Wrocław. The construction is based on the EU07
PKP class EU07
EU07 is the name for a Polish electric locomotive in service of the Polish railway operator PKP. This locomotive was designed as universal locomotive, and as such is used in both for freight and passenger traffic.-Technical data:...

 locomotive.

History

In the 1970s PKP tended to increase speed of Polish passenger trains, what resulted mainly in building CMK line (Trunk Line) and modernisation of EU05 locomotives into EP05
PKP class EP05
The EP05 is a Polish modification of Czech electric locomotive EU05 used by Polish railway operator -History:The locomotive was produced in the years 1957–1960 in three types: 20E1, the prototype, 30E1 and 30E2...

 series. Meanwihile a project was opened to introduce new electric locomotive
Electric locomotive
An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or an on-board energy storage device...

 able to pull trains with speed exceeding 125 km/h, based on British
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 EU06
PKP class EU06
EU06 is a class of electric locomotives in service with the Polish state railway PKP.-Technical details:EU06 has driving cabs at both ends. The locomotives are equipped for multiple working which allows one driver to drive two coupled engines from one cab. One locomotive can haul passenger trains...

 and local EU07 machines.

In 1972 the first prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...

 left Pafawag works and until 1976 a total number of 15 units had been produced. Further production was ceased due to huge orders of freight locomotives and insufficient funds for importing foreign parts for the machine.

EP08 were the first locomotives in Poland to exceed the top speed limit of 125 km/h and contributed (alongside with EP05 class) into fast development of high speed passenger connections. All machines of this class station in Warsaw
Warsaw
Warsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...

 but as top speed on Warsaw-Poznań
Poznan
Poznań is a city on the Warta river in west-central Poland, with a population of 556,022 in June 2009. It is among the oldest cities in Poland, and was one of the most important centres in the early Polish state, whose first rulers were buried at Poznań's cathedral. It is sometimes claimed to be...

 line had been increased to 160 km/h they are no longer used on regular basis and serve as auxiliary machines, mostly pulling trains from Warsaw to Zakopane
Zakopane
Zakopane , is a town in southern Poland. It lies in the southern part of the Podhale region at the foot of the Tatra Mountains. From 1975 to 1998 it was in of Nowy Sącz Province, but since 1999 it has been in Lesser Poland Province. It had a population of about 28,000 as of 2004. Zakopane is a...

.

Technical data

As the EP08 is tightly based on EU06 and EU07 locomotives it is important to compare those series while writing about technical features. EP08 is a Bo-Bo
Bo-Bo
A Bo-Bo or Bo′Bo′ is a locomotive with two independent four-wheeled bogies with all axles powered by individual traction motors...

 locomotive with four axles mounted on two bogie
Bogie
A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...

s. Each axle is propelled separately by an EE541a traction motor
Traction motor
Traction motor refers to an electric motor providing the primary rotational torque of a machine, usually for conversion into linear motion ....

. The cab has two identical crew compartments on both ends.

The main differences between EP08 and previous EU07 locomotives are as follows. Transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...

 was changed from 79:18 into 77:24 what resulted in possible top speed of 160 km/h. However, the machined performed poorely driving with such speed, so the top speed was set to 140 km/h. First five units were equipped with plain bearing
Plain bearing
A plain bearing, also known as a plane bearing or a friction bearing is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore the journal slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole...

s what proved insufficient for higher speeds and as a result all these locomotives were rebuilt as EU07 series (numbers 241 to 244). In later units roller bearing's were used.

Another significan change comparing to EU07 series was exchange of traction motors to newer EE541g type with higher isolation class. Windscreens were changed to 14 mm thick ones with heating layer and pneumatic wiper
Wiper
Wiper may also refer to:* Wiper, a term for a hybrid striped bass* Wiper, a term for the moving contact on a potentiometer* Wiper * Windscreen wiper* Wiper, another brand name for the Lawnbott...

s. However, some solutions from EU07 locomotives which were rather faulty, were copied into this machines, like poor access to internal devices.

EU08 is suited for multiple steering work. Locomotive's cab resembles those of EU06 and EU07, but have different, orange and brown painting. Since June 2007 PKP Intercity
PKP Intercity
PKP Intercity is a company of PKP Group responsible for long-distance passenger transport. It runs about 350 trains daily, connecting mainly large aglomerations and smaller towns, also servicing most of the international trains....

has started repainting those machines into new, blue and white colours.
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