Modernization of Sofia - Plovdiv railway

The Railway line Sofia – Plovdiv in Bulgaria is part of The Trans-European Corridor No IV (Dresden - Prague - Bratislava - Gyor - Budapest - Arad - Kraiowa - Sofia - Plovdiv – Istanbul) and Corridor No VIII (Durrës/Vlora – Tirana – Skopje – Sofia – Varna/Burgas) and its modernization is among the priority projects financed with EU funds through the Operational Programme "Transport” for period: 2007 – 2013.

Quick Facts

Purpose: Railway line

Location: Sofia – Plovdiv, Bulgaria

Client: National Company Railway Infrastructure, Bulgaria

Services provided: Preparation of detailed site development plans and basic designs


Railway line between Sofia and Septemvri town is 103 km long and is divided into 3 sections. The second section is located between Elin Pelin and Ihtiman railway stations, length app. 30.5 km, passes through mountainous land and has the following parameters: maximum gradient 25‰, minimum radius 300 m, design speed in the section from 65 to 130 km/h (maximum speed after modernization: up to 160 km/h). It is the most difficult part of the railway line Sofia - Plovdiv due to the complex topography of the terrain.

In January 2015, the state company National Company Railway Infrastructure (NCRI), following a public-procurement procedure, awarded an assignment to the Consortium named “ELIH” for provision of consultancy services for: Preparation of detailed site development plans and basic designs for the modernization of the section of Sofia – Plovdiv railway line situated between Elin Pelin and Ihtiman railway stations.

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Railway Sofia Plovdiv Situation 1


Consortium ELIH is led by Transgeo Ltd (Bulgaria), with partners: Sweco Energoproekt Jsc (Bulgaria), HTG Ingenieurbüro Für Bauwesen GmbH (Germany), Kramp-Engineering Ltd (Bulgaria), and ITM Project Ltd (Bulgaria).

According to the work distribution between the partners, the share of Sweco Energoproekt Jsc in the implementation of the contracted services is approximately 20% and includes the following:

  • Geological explorations of tunnel sections;

  • Hydrologic and hydraulic investigations for the hydraulic civil structures along the railway section Elin Pelin – Ihtiman;

  • Measures for optimization of construction costs of tunnels;

  • Basic Designs for Tunnel 2 (twin railway tunnel with length 6 700 m and cross-section area of each tube of 81 m2), including: civil structures (tunnel linings, portals, cross-connections, water reservoirs), drainage and dewatering system;

  • Basic Designs for systems ventilation, lighting, fire alarm, fire safety and GSM-R communication systems in the tunnels;

  • Basic Designs for the crossings with other infrastructure: water mains and sewers, power lines, gas pipelines, underground communications lines, etc.;

  • Technical specifications for construction and installation works in tunnels.

    Modernization of Sofia – Plovdiv railway line will solve one of the most problematic sections of the railway network in Southeast Europe, located on the shortest link between Western Europe and the Middle East and Asia through the newly built tunnel under the Bosphorus. As a result, a quality railway link between the cities of Ankara, Istanbul and Sofia will be created, linking them to the other capitals of the EU member states.

Railway Sofia Plovdiv Situation 2

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