Sofia Metro Linie 2
Bulgaria, Sofia
2010 – 2011

The metro system in Sofia was to be expanded. The current Metro Line 1 was to be supplemented by an additional Line 2 in the form of a 17-kilometer section planned from the Obelya terminal via Nadejda, the central railway station and the National Art Gallery as far as the Hladilnika district. This involved underpassing railway tracks, a historic church and developed land along a 3.8-kilometer section from Nadejda Junction to Sveta Nedelia Square. At some points along the route, minimum overburden was a mere three meters. A sensitive undertaking which needed to be mastered without subsidence or elevations.

Herrenknecht supplied the EPB Shield as well as other additional equipment for a most efficient tunnelling process such as: multi-service vehicles for transporting the segments on the site, a tunnel belt conveyor system for transporting excavated material, 14 moulds for segment production as well as a guidance system for determining TBM positions and navigation during advance, including a ring sequence program.

Since the start of tunnelling, the teamwork of tunnelling specialists on site and Herrenknecht technology proved of value: more than 220 meters of new tunnel were built in one week. On August 29, 2011, the jobsite crew celebrated breakthrough after 3,770 tunnel meters.

Data Sheet

Country, Location

Bulgaria, Sofia


2010 – 2011




Soft ground
Gravel, clay, sand, silt

Tunnelling length

3,770 m

Machine Data

1x EPB Shield:
Diameter: 9,360 mm
Lining method: Segmental lining
Cutterhead power: 3,200 kW
Torque: 20,533 kNm

Your contact person Contact us

Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.