[3] The system is operated by Metro Warszawskie, a company owned by the city, and managed by Public Transport Authority in Warsaw.

[4][5] The initial segment of M2, measuring 6.3 kilometres (3.9 miles) with seven stations,[2] one of which, Świętokrzyska, includes a transfer between the two lines, was opened on 8 March 2015.

Proper preliminary planning and boring work were initiated by the Warsaw Tramway Authority in 1925, with construction expected to start in the late 1920s.

There, the line was to go overground, cross the river through a newly built bridge and proceed to the easternmost railway station of Warszawa Wschodnia.

Although the majority of pre-war projects were destroyed during the war, most of the engineers behind their creations survived and returned to their city to take part in its rebirth.

Thus, the Office for the Reconstruction of Warsaw (BOS) commissioned several engineers to prepare a project for a fast urban railway (SKM) crossing the city in a deep cutting.

Instead, in 1948 communist planners developed a different concept with the new SKM morphing into a rapid transit line at a depth of up to 15 metres (49 feet).

In the 1950s, as the Cold War raged on, Soviet strategic plans required that a secure transport link across the river Vistula be built.

By 1953 only 771 m (843 yd) of tunnels had been built; after the death of Joseph Stalin and the start of a period of détente, all work was halted under the pretext of technical difficulties.

However, the planning phase proceeded at a very slow pace and the economic situation prevented all successive governments from actually starting serious work.

Lack of funds, technical difficulties, shortage of materials and outdated tunnelling methods meant that the work progressed very slowly, sometimes at a speed no greater than 2 m (6 ft 7 in) per day.

[13] On 11 March 2016, a 1 billion PLN (€225 million) contract was awarded to the Italian company Astaldi to build the first phase of the north-east M2 extension with 3.2 kilometres (2.0 mi) of track and 3 stations: Szwedzka, Targówek Mieszkaniowy, and Trocka.

Turkish construction firm Gülermak was commissioned in November 2018 to complete the three western-most stations on the line – Lazurowa, Chrzanów and Karolin.

They first arrived in Warsaw in 1990 as a "gift" from the USSR, five years before the Metro's opening, from the Metrovagonmash plant in Mytishchi near Moscow (model 81-717.3/714.3 - 10 carriages).

[28] In 2006, additional 30 carriages were ordered from Russia to extend the existing 81-series to the target length of six cars, with deliveries taking place up to 2007.

Originally the 81-series and Alstom Metropolis trains were painted in two horizontal stripes of equal width, the upper one white and the lower one red, with a blue bar identifying the M1 line between them.

For the Simens Inspiro a livery with a yellow and red stripe under the windows was chosen in order to resemble the color scheme of the surface public transport taken from the flag of Warsaw.

[30] With the delivery of the Škoda Varsovia the obsolete 81-series is being gradually retired, units in good technical condition have been donated for spare parts to Kyiv[31] and Kharkiv,[32] where trains of the type are still common.

A single trainset of this is to be kept in working order as a museum exhibit and seasonal operation while 3 others remain in Warsaw for spare parts.

It also does not directly connect to the Warszawa Central railway station, with the nearest stop being over 400 metres (1,300 feet) to the east.

Until the opening of M2 in March 2015, the metro system was confined to the western bank of Vistula, thus doing nothing to ease traffic problems on Warsaw's bridges: a major bottleneck between the city center and the eastern Praga district.