section_path: Transport/Public transportation/The City Line Project
section_name: The City Line Project
paragraph_text: The City Line Project
  
  With an estimated cost of SEK 16.8 billion (January 2007 price level), which equals 2.44 billion US dollars, the City Line, an environmentally certified project, comprises a 6 km (3.7 mi) -long commuter train tunnel (in rock and water) beneath Stockholm, with two new stations (Stockholm City and Stockholm Odenplan), and a 1.4 km (0.87 mi) -long railway bridge at Årsta. The City Line was built by the Swedish Transport Administration in co-operation with the City of Stockholm, Stockholm County Council, and Stockholm Transport, SL. As Stockholm Central Station is overloaded, the purpose of this project was to double the city's track capacity and improve service efficiency. Operations began in July 2017.
  
  Between Riddarholmen and Söder Mälarstrand, the City Line runs through a submerged concrete tunnel. As a green project, the City Line includes the purification of waste water; noise reduction through sound-attenuating tracks; the use of synthetic diesel, which provides users with clean air; and the recycling of excavated rocks.