Sofia Metro

Sofia Metro is the rapid-transit network serving Bulgaria's capital and the only metro system in the country. It is a municipal public-transport service associated with Metropolitan EAD and forms one of the principal high-capacity components of Sofia's wider bus, tram and trolleybus network. The system began passenger operations on 28 January 1998, after several decades of planning, engineering studies and interrupted construction. The network was conceived to address Sofia's growing population, intense radial passenger flows and worsening road congestion and air-quality pressures. Its original development plan organized the network around major diameters crossing the city centre and extending toward peripheral residential and employment districts. Construction was technically difficult because central Sofia contains archaeological remains and successive historical layers. The Serdika station area, for example, incorporates or displays archaeological discoveries from the ancient Thracian and Roman city of Serdica. Parts of the infrastructure around the National Palace of Culture were also constructed in connection with that complex before the relevant metro route entered service. The first operational section connected the western Lyulin district with the city through five stations. Subsequent extensions reached the city centre, Obelya, the eastern districts around Mladost and the Sofia Airport area. A second major corridor linked Obelya and Nadezhda with Sofia Central Railway Station, the National Palace of Culture and Lozenets. The third line introduced a newer operating concept, including Siemens Inspiro trains, platform screen doors and automated-operation capability. The network's lines are commonly identified by both numbers and colors: M1 is generally associated with the red corridor, M2 with the blue corridor, M3 with the green corridor and M4 with the airport-oriented yellow corridor. Operational arrangements and line identities have changed as branches and through-services have been reorganized. The metro connects large residential areas such as Lyulin, Nadezhda, Mladost and Ovcha Kupel with central Sofia, major interchange points, business districts, cultural institutions and Sofia Airport. Its service offering consists of rapid rail journeys, station interchange, fare media and passenger-information services rather than conventional consumer products. Passengers can use paper tickets, travelcards and contactless bank-card or mobile-wallet payment. Contactless payment was introduced across the network in 2021, with fare capping described in published system information. Sofia Metro uses several generations of rolling stock. Early trains were based on the 81-717/714 family manufactured by Metrowagonmash, while later Metrowagonmash 81-740/741 Rusich trains expanded capacity on the established lines. The M3 line uses Siemens Inspiro trainsets and differs technically from the older lines, including the use of pantographs rather than third-rail collection. The system has also added platform safety barriers: vertically opening rope screen doors on selected older-line stations and horizontally opening platform screen doors on M3 stations. The brand's public positioning is functional and civic: fast, frequent and comparatively reliable urban mobility that links peripheral housing estates and employment centers with central Sofia and the airport. Its identity is closely tied to infrastructure expansion, European-supported transport investment, archaeological sensitivity in the city centre and the modernization of fare collection and passenger safety. Planned and proposed extensions have included additional western, eastern and southern branches, but the timing and scope of future projects remain subject to public funding, construction and municipal decisions.

Plans for a metro in Sofia date from the 1960s, when the city began examining a high-capacity underground system to handle expanding residential districts and heavy radial travel into the centre. Formal development was complicated by the city's long history and dense central fabric. Construction began during the 1980s and involved substantial demolition and major civil works. The project then encountered a severe interruption in the early 1990s as funding became scarce and engineering challenges increased. The first passenger section finally opened on 28 January 1998. It covered 6.5 kilometres and five stations between the western Lyulin area and the city. The route was progressively extended through Opalchenska and Serdika, with the latter opening in 2000 near the historic centre. Archaeological remains uncovered during construction became an important feature of the network, particularly at Serdika, where station design accommodates evidence of ancient Serdica and associated Thracian and Roman layers. The western branch reached Obelya in 2003. During the second half of the 2000s, construction resumed on routes toward the eastern districts and Mladost. The Vasil Levski Stadium–Mladost 1 section opened in May 2009, and the missing central segment followed in September of the same year. These openings connected the previously separate western and eastern operating sections and created a continuous corridor between Obelya and Mladost 1. The line was subsequently extended to Business Park Sofia in 2015. A second major corridor was developed with substantial European Union support alongside national and municipal funding. Works between Nadezhda, the central railway station, the National Palace of Culture and Lozenets began in 2008, while the Obelya–Nadezhda section followed in 2010. Both portions entered service on 31 August 2012. The corridor was then extended toward Sofia Airport, with the airport section opening in April 2015, and southward to Vitosha in July 2016. Operational naming and through-running arrangements have evolved as the airport branch and the western corridor were reorganized. The third line represented a technical modernization of the system. Its design included a mixture of underground and above-ground stations, new train technology and platform screen doors. Construction of the principal central section began in the mid-2010s after tenders and design work. Siemens was selected to supply the line's trains, which use pantographs rather than the third-rail collection used by the older lines. The first M3 section, between Krasno Selo and Hadzhi Dimitar, opened in August 2020; the extension to Gorna Banya opened in April 2021. Sofia Metro has used several generations of rolling stock. The earliest fleet was based on Metrowagonmash 81-717/714 vehicles delivered before the first passenger opening, many of which were later refurbished. A second generation of 81-740/741 Rusich trains was delivered from 2005 onward. Siemens Inspiro three-car sets were supplied for M3 between 2016 and 2021. In 2023, Škoda Transportation won a contract for eight additional four-car trains intended to replace some older Metrowagonmash units. The system has also modernized its fare collection. In addition to conventional tickets and period passes, contactless bank-card and mobile-wallet payment became available across the network in November 2021. Safety infrastructure varies by line: selected stations on the older lines use vertically opening rope screen doors, while M3 stations use horizontally opening platform screen doors. Further proposals have included a branch toward Slatina and Geo Milev, western extensions and routes serving Studentski Grad and Iliyantsi. These projects are subject to design, procurement, financing and construction decisions and should not be treated as operational service unless separately confirmed.

• 2021

  Gorna Banya extension and contactless payment

  [1]Sofia Metroen.wikipedia.org

  M3 reaches Gorna Banya, while contactless card and mobile-wallet fare payment becomes available.

• 2020

  M3 begins operation

  [1]Sofia Metroen.wikipedia.org

  The first section of the green M3 line opens with new trains and platform screen doors.

• 2016

  Vitosha extension opens

  [1]Sofia Metroen.wikipedia.org

  The southern corridor is extended to Vitosha station.

• 2015

  Airport and Business Park extensions open

  [1]Sofia Metroen.wikipedia.org

  The network reaches Sofia Airport and Business Park Sofia.

• 2012

  Second corridor opens

  [1]Sofia Metroen.wikipedia.org

  The Nadezhda–central Sofia–Lozenets corridor enters service.

• 2009

  East-west connection completed

  [1]Sofia Metroen.wikipedia.org

  Extensions toward Mladost and the opening of the central gap establish continuous service between Obelya and Mladost 1.

• 2003

  Obelya is connected

  [1]Sofia Metroen.wikipedia.org

  The western route reaches Obelya housing estate.

• 1998

  First section opens

  [1]Sofia Metroen.wikipedia.org

  The first five-station, 6.5-kilometre section begins passenger service on 28 January.

• 1980

  Construction starts

  [1]Sofia Metroen.wikipedia.org

  Construction begins during the 1980s after planning and technical preparation.

• 1960

  Metro planning begins

  [1]Sofia Metroen.wikipedia.org

  Sofia begins developing plans for a metro system to address long-term urban growth and concentrated passenger flows.

A core municipal rapid-transit service positioned around fast cross-city travel, network expansion, airport access, modern ticketing and improved urban mobility.

• Metro line · 1998

  M1 Red Line

  The original principal corridor of Sofia Metro links western districts, including Lyulin and Obelya, with central Sofia and eastern areas around Mladost. Its development occurred in stages from the first 1998 opening through later central and eastern extensions. The line uses the older system's third-rail infrastructure and a mixture of refurbished early trains and later rolling stock.

• Metro line · 2012

  M2 Blue Line

  M2 forms the central and southern corridor connecting Obelya and Nadezhda with Sofia Central Railway Station, the National Palace of Culture, Lozenets and Vitosha. It is one of the principal routes through central Sofia and shares parts of the network's western infrastructure with other services.

• Metro line · 2020

  M3 Green Line

  M3 connects southwest and northeast Sofia through the centre, with service developed in stages from 2020 and 2021. It introduced Siemens Inspiro trains, pantograph power collection, platform screen doors and a higher degree of automation than the older lines. Its southern route reaches Gorna Banya.

• Metro line · 2015

  M4 Yellow Line

  M4 identifies the airport-oriented service serving the eastern corridor and Sofia Airport. The airport extension includes underground and above-ground sections and provides a direct rail connection between the city metro network and the airport.

• Airport metro service · 2015

  Sofia Airport connection

  The Sofia Airport extension provides metro access to the capital's airport through a 4.968-kilometre section with four stations. It expanded the system's role beyond residential and central-city travel and made the metro a significant airport-transfer option.

• Transit payment service · 1998

  Fare and ticketing services

  Sofia Metro sells single tickets and daily, monthly and annual travel products. Published system information also describes contactless payment by bank card and supported mobile wallets, with the fare charged through station validators and associated fare rules.

• 2023

  Order new Škoda metro trainsProduct launch

  Background

  Part of the established fleet relied on older Metrowagonmash vehicles delivered before or during the early development of the system.

  Action taken

  Škoda Transportation won a contract to supply eight four-car air-conditioned metro trains for deployment on the older lines.

  Aftermath

  The order was intended to modernize part of the fleet and replace some older vehicles.

  Contract value. EUR 65 million (2023 contract award)

  Source

• 2021

  Introduce contactless fare paymentStrategy

  Background

  The metro sought to simplify access and reduce dependence on paper tickets and cash transactions.

  Action taken

  Contactless bank cards and supported mobile wallets were enabled at stations from November 2021.

  Aftermath

  Passengers gained a more convenient electronic payment option alongside conventional tickets and travel passes.

  Source

• 2015

  Adopt dedicated M3 rolling stockProduct launch

  Background

  The third line required trains suited to its technical specification, including pantograph power collection and automated-operation capability.

  Action taken

  Siemens won the procurement for M3 trains, leading to the delivery of Inspiro three-car sets between 2016 and 2021.

  Aftermath

  M3 entered service as the network's most technically distinct line.

  Source

• 2014

  Tender for M3 central sectionProduct launch

  Background

  The planned third line was redesigned around a central tunnel, interchange stations and a combination of underground and above-ground construction.

  Action taken

  Sofia announced a construction tender for the central section of M3, including approximately seven kilometres of route and seven stations.

  Aftermath

  The line's first sections opened in 2020 and 2021 with new trains and platform safety doors.

  Source

• 2008

  Proceed with the second metro corridorStrategy

  Background

  Sofia pursued a major corridor linking Nadezhda and Obelya with central Sofia and Lozenets to address strong northwestern and southern passenger flows.

  Action taken

  Construction began on the central section in December 2008, with European Union support covering a substantial share of the investment and the remainder provided through state and municipal budgets.

  Aftermath

  The corridor opened in 2012 and was later extended toward Sofia Airport and Vitosha.

  Source

1. 1Sofia Metroen.wikipedia.org
2. 2Metropolitan EAD official websitemetropolitan.bg