Completion of construction works on the Project "Modernization of the Pazardzhik - Stamboliyski railway section part of the Trans-European railway network"

Construction works on the overhead line: the existing overhead line was dismantled and a new overhead line has been installed in accordance with the relevant regulatory requirements and the design. The poles are reinforced concrete poles of the type SBMK 37/11.15 or SBMK 57/11.15 or steel lattice poles with П-shaped cross section, made of galvanized steel and completed with a protective paint system.

The concrete poles have been laid in concrete foundations. The steel lattice poles have been mounted on concrete foundations using anchor bolts. A total of 760 poles - concrete and steel lattice ones – have been erected. The overhead line is suspended from cantilever arms or rigid cross members (at the stations). The structure of the rigid cross members includes two vertical columns supporting a crossbeam suspended on a cable. The overhead line (catenary) is of a chain type with a CuAg 0.1 contact wire with a cross section of 120 mm2 at the open track sections, and a CuAg 0.1 contact wire with a cross section of 120 mm2 in the area of the stations – for the main tracks and S-links, and a CuMg 0.2 contact wire with a cross section of 100 mm2 for the secondary tracks.

The system height at the suspension points is 1.45m. The height of the contact wire is 5.50 m from the railhead level. The carrying cable is Bz II (Cu Mg 0.4) with a cross section of 70 mm2 (19 x 2.1 mm) between the stations, and a bronze carrying cable BzII (CuMg 0.4) with a cross section of 70 mm2 for the main tracks and BzII (CuMg 0.4) - 50 mm2 for the secondary tracks in the area of the stations. The system between the stations is made of a bare bronze flexible conductor BzII - 10 with a cross section of 10 mm2. In the area of the stations, the contact wire is suspended on a carrying cable at the poles with a string made of a bronze cable Bz II 25 mm2 and smaller 10 mm2 strings.

The terminals for the string are made of the material CuNiSi - "KRUCH" model. The strings are made of a bronze cable Bz II 7x6.3mm with a cross section of 25 mm2. The cantilever arms are insulated by polymeric insulators. The compensating devices are of the KSS monoblock type with a latch. The cables used for the compensating device are flexible stainless steel strands. The opposite conductor is aluminium stranded 184-All/30 (32) -St IA.

The anchoring of the back feeder is rigid - on the poles of the middle anchors of the overhead line. The poles are grounded. A single-strand steel, galvanized wire with a diameter of 20 mm is used for the anchor pull-offs of the reinforced concrete anchor poles, a stranded flexible copper conductor with cross section of 190 mm2 (2 x 95 mm2) for the lengthwise electrical connectors and connections between section disconnectors and catenary, a single-strand steel, galvanized wire with a polymer coating - for the pole-rail grounding connections, electric connectors between rails or between tracks, a stainless steel cable 1.4401-ANSI 316 DIN 3060 7x19, 1570 Nmm2, d = 12.0mm – for pull-offs for the rigid cross members, terminals for the strings, power connectors, anchoring and connecting terminals, carrying terminals, tensioning devices for the contact wire, electrical connectors, insulators and section insulators, motor-driven sectional disconnectors, actuators for the disconnectors, surge protection, and protection against bird nesting.

All the poles are numbered and bear the relevant signage.