were rebuilt together with the tunnel under the country's capital. As a part of the Ministry of Communication, the Bureau for Railway Electrification was founded. The first projects were to rebuild all lines that had been electrified before the war, and then the Warsaw–Żyrardów–Skierniewice–Koluszki and the Warszawa–Sochaczew lines would be electrified. The electrification was planned to bring 3000V AC into Polish railways. The modernised version of PKP class Pt31 locomotive started in 1948, the locomotive gaining a new name, Pt47. Reconstruction of German S-Bahn EMUs started the same year, which required building overhead lines in the Tricity area. Those EMUs were renamed EW90, 91 and 92 and soon after (in 1951) started operating on SKM lines. In 1949 the construction of Tomaszów Mazowiecki–Radom line was completed. The 50s in Polish railways were a time of serious development and improvements. In 1950, construction of TKt48 locomotives started and two years later a prototype of the Ol49 steam locomotive was built. 1953 brought several new types of electric rolling stock into PKP. Ten units of EP03 electric locomotives and 40 units of EW54 EMUs were ordered from Sweden. EW54 EMUs were sent to operate on lines connecting Warsaw with Mińsk Mazowiecki, Żyrardów and Sochaczew. Meanwhile, EP04 and EU20 locomotives were ordered from the DDR, along with EN56 and ED70 EMUs. Polish production in that period included PKP class EW53 EMU and PKP class EP02 locomotive. In 1954 the prototype of the last heavy freight steam engine – PKP class Ty51 – was built. New lines opened that year are Skierniewice–Łuków line and Sitkówka–Busko Zdrój line. Przemyśl-Zagórz trains travelled through the Soviet Union without stops. High speed Central Rail Line (designed in 1977 for speed equal 250 km/h) and Broad Gauge Metallurgy Line (1979) were constructed. The highest speed reached by railway in Poland during the communist period was 160 km/h in 1987 as a regularly scheduled operation from Warsaw to Kraków. It was premiere of the newest Polish electric locomotive EP09. Present-day Poland On 14 December 2014 PKP Intercity Pendolino trains under the name 'Express Intercity Premium' began operating on the CMK line (224 km line from Kraków and Katowice to Warsaw) with trains reaching 200 km/h (124 mph) as a regularly scheduled operation. There is a plan by PKP PLK to increase speed to 250 km/h on whole line soon. The "Y" High-speed rail in Poland construction has been cancelled. The