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First 70 meters of the longest two-pipe railway tunnel in our country dug

First 70 meters of the longest two-pipe railway tunnel in our country dug
24.08.2021

The first 70 meters of the longest two-pipe railway tunnel ever built in Bulgaria have already been dug. It is 7 km long and is a component of the large-scale Elin Pelin-Kostenets Railway Project, whose implementation started a little over a month ago.

At the end of the previous day, the Minister of Transport, Information Technology and Communications Georgi Todorov inspected the construction activities of the site. "What I see is that work is being done at a very good pace on the spot. At the moment, the builder has completed work on the eastern and western portals of the tunnel and is carrying out excavation works in the tunnel body", the Minister added.

He pointed out that it was one of the important strategic projects for Bulgaria. "Its implementation will improve the connectivity on the main railway line from the direction East - West, which is part of the European Corridor No. 8 and the TEN-T Network passing in our country. It is therefore important not to delay, despite technical and operational challenges. The implementation of continuous control over the entire process is also important to ensure high quality construction", Minister Georgi Todorov said.

The tunnel is expected to get completed in 3 years. The technology for building the facility includes implementation by a new Austrian method. It is one of the most commonly used methods of tunnel construction, providing flexibility and safety.

In addition to the long tunnel, another tunnel facility is currently under construction, with a length of almost 1 km, as contractor representatives explained. The geology of the terrain in which the tunnels are being built is the big challenge, according to project manager Plamen Mitov. With each change in the geological conditions, the type of fortification is determined - heavier or lighter. In the process of work it changes. The tunnels are operated around the clock and adequate and quick decisions have to be made constantly, Mitov explained.

"One section is being excavated and, depending on the geology at the moment, the advance should be 1.5 to 2 meters. Strengthening is carried out immediately for safety reasons, both for people and for equipment. Until last week, work was done mechanically, with excavators. Blasting activities are already underway as a solid rock mass has been reached. Every two meters it is first waited for the smoke and harmful gases from the explosion to come out, then the material is dug up and taken out, the first reinforcement is made, a net, frames and others are laid. This is a cyclical process of repetition, and the most important thing is the safety of the people working on the site", Plamen Mitov said.

The railway line from Elin Pelin to Kostenets, 51 km long, is the most complex section of the Sofia-Plovdiv route. In order to overcome the mountainous terrain through which the high-speed railway line will pass, almost half of the section will be built underground. It is planned to build over 20 km of tunnels and 3 km of bridges. The design speed of the new route is up to 160 km/h for passenger trains and 120 km/h for freight trains.

The modernization of the entire track is worth BGN 1.024 billion, which will be provided by two operational programs - Operational Program on Transport and Transport Infrastructure 2014-2020 and Transport Connectivity Program 2021-2027.