Metro stations “Hadzhi Dimitar”, “Teatralna” and “Orlov most” from Sofia’s third metro line are already a part of Trace Group metro construction history

The official opening ceremony of Sofia’s third metro line took place on 26 August, 2020. The project first stage having a length of 8 km and covering 8 metro stations was put into operation on the same day. Metro stations 5 “Hadzhi Dimitar”, 6 “Teatralna” and 8 “Orlov most”have been designed by the team of Arch. Konstantin Kosev and constructed by engineers and builders of the team of “Trace Group”. Project manager has been Dipl. Eng. Petar Kostov. The three mentioned metro stations were implemented by Trace and partner companies in consortiums. The other two metro stations that have been executed by Trace within Sofia’s third metro line – MS 17 and MS “Gorna Banya” are currently in a test mode.

MS 5 and MS 6 have been difficult to implement due to diverse geological conditions through which the tunnel section passes, high groundwater and proximity of the stations to Perlovska River correction (the northern entrance of MS 5 passes under the river and exits on the sidewalk of “Vladimir Vazov” Blvd.). In an interview, Dipl. Eng. Boyan Delchev, Trace CEO said: "The way in which the transition between metro stations 5 and 6, under an existing railway line, at an extremely little height from the top of the tunnel to the rail level, sand and water soils, is an example for the fact that Bulgarian engineers know what to do and how to do it. The tunnel boring machine reached MS 5, which required a full meet of deadlines”. MS Orlov Most is the deepest metro station in Sofia.

MS 18 in “Ovcha kupel” R.D. includes construction of two stations, the adjacent line station with a bretelle and a railway station. For the purpose of safety and fast movement of the citizens, a covered pedestrian connection has been built, passing under the railway line (Sofia-Pernik-Radomir) and the Sofia Ring Road, which connects "Ovcha Kupel" R.D. and "Gorna Banya" R.D.

The entire central section of the Third Metro Diameter was dug by the method of so-called shield passage which is suitable for long tunnels. The tunnel at MS 18 due to its specificity and length was dug according to the New Austrian tunnelling method. It was more labor intensive and slower to progress than other conventional methods. Its huge advantage was that it did not affect the adjacent infrastructure in any way. In this case, it passed under Sofia Ring Road and under the railway line – they both and the local engineering infrastructure have been intact, which saved significant inconvenience to citizens.

The construction activities that have been performed on the project include: construction of the structure; railway road; new type of catenary and cable network for Bulgaria; electrical systems and installations; transport automation, dispatch management and control system; telecommunication systems (transport communication system, dispatching system, train radio communication system, sound and alarm system, control television system, clock system, fire alarm system, access control system and security system, automatic charging system, tunnel ventilation), etc.

By the inclusion of the Green Line within the Third Metro Diameter, the passenger flow is expected to reach 110 thousand showers per day, car traffic will be reduced by 25%, which will lead to a reduction of harmful emissions by more than 11 thousand tons per year.

MS "Hadzhi Dimitar" video is available here.

MS "Teatralna" video is available here.

MS "Orlov most" video is available here. 

MS "Gorna Banya" video is available here.