"Modernization of the Pazardzhik - Stamboliyski  railway section from the end of Railway Switch № 5 (km 119+624) on Track № 1 and from the end of Railway Switch № 1 (km 119+692) on Track № 2 at the eastern throat of Pazardzhik Station, to the end of Railway Switch № 3 (km 138+755) on Track № 1 and to the beginning of Railway Switch № 1 (km 138+810) on Track № 2 at the western throat of the Stamboliyski  Station, inclusive of both Ognyanovo and Stamboliyski  Stations" 

This is a I (first) category construction according to Art. 137, para. 1, item 1, letters "a" and "b" of the Spatial Planning Act (SPA), and Art. 2, para. 1, item 3 of Regulation № 1 on the nomenclature of the type of constructions, 2003. Location: National Railway network of the Republic of Bulgaria - Septemvri - Plovdiv - Pazardzhik - Stamboliyski railway section, Pazardzhik District, on the territory of Pazardzhik Municipality, and Plovdiv District, on the territory of Stamboliyski  Municipality. Completed under Building Permit № RS- 67/20.11.2013, issued by the Ministry of Regional Development and Public Works (MoRDPW)

Modernisation of the main electrified double railway line designed for a design speed of 160 km/h, and overhead line designed for 200 km/h. (with a tolerance of +10% on these values), subject to the relevant national and European technical regulations, incl. the Technical Specifications for Interoperability. 
-    Construction works on the railway track, platforms, water drainage: a design solution for the railway track between the stations Pazardzhik-Ognyanovo and Ognyanovo-Stamboliyski has been implemented to provide a minimum distance of 4.40 m between the track centerlines of Track №1 and Track № 2 for a design speed of 160 km/h, as required by Regulation 55. The railway track has UIC 60E1 rails on reinforced concrete sleepers with elastic fastenings. The railway track length: 
a./ between the stations: Pazardzhik-Ognyanovo on Track № 1 is 7572 m, and on Track № 2 is 7654 m; 
b./ between the stations: Ognyanovo-Stamboliyski  on Track № 1 is 8675 m, and on Track № 2 is 8669 m; 
c./ Ognyanovo Station: along Track № 1 (PO-track 2) - 1100 m, and along Track № 2 (PO-track 3) is 1104 m. The existing arrangement at the station's two throats has been replaced by two S-links. The new useful lengths of the tracks are as follows: - new PO-track 1 – 594 m; new PO- track 2 – 682 m; new PO-track 3 – 682 m; new PO-track 4 – 609 m. New protective dead-end railway tracks have been constructed at km 127+700 – from the Railway Switch № 16 on the forth track, and at km 128+339 – from Railway Switch № 15 on the forth track. A partial reconstruction (95 m) of the manoeuvring track at km 127+684 has been completed within the station area, from Railway Switch № 14 on the first track, where the useful length has been increased by 30 m, and another 80 m on the loading track at km 128+384 - from Railway Switch № 13 on the first track, effectively increasing the useful length by 25 m. 60E1 rails on reinforced concrete sleepers with elastic fastenings have been used for the railway track along the main tracks and railway switches, while the rails used for the other tracks are second hand 49E1 rails. All the existing interim platforms were demolished and new platforms were built as follows: Platform 1 (front) – 130 m long, where the height of the top edge of the platform measured from the railhead is 0.25 m along a 100 m section of the platform, and the height of the top edge of the platform measured from the railhead is 0.55 m along the remaining 30 m of the platform; Platform 2 – 7.10 m wide and 200 m long, where the height of the top edge of the platform measured from the railhead is 0.55 m; Platform 3 – 5.5 m wide in the area of the pedestrian underpass, and 3.00 m wide along the rest of the platform, and 200 m long, where the height of the top edge of the platform measured from the railhead is 0.55 m. Platform canopies on a steel structure have been constructed on the second and third passenger platforms. Passenger access to the platforms is provided through a new pedestrian overpass linking Platforms 2 and 3 at km 127+940, with lifts installed at each entrance and exit point of the overpass. A pedestrian ramp for access of persons with reduced mobility has been constructed between Platform 1 and Platform 2.
d./ Stamboliyski  Station: along Track № 1 (PO-track 2) - 1637 m, and along Track № 2 (PO-track 3) - 1730 m. The S-links at the outgoing station throat facing Plovdiv in the area of Stamboliyski Station have been replaced with high-speed Railway Switches 1:18.5-1200. Track 4 has been dismantled to free space for a new platform. 60E1 rails on reinforced concrete sleepers with elastic fastenings have been used for the railway track along the main tracks and railway switches, while the rails used for the other tracks are second hand 49E1 rails. The following useful track lengths have been achieved: PO-track 1 – 788 m; PO-track 2 – 831 m; PO-track 3 – 656 m; PO-track 4 - 523 m; PO-track 5 – 509 m; PO-track 6 – 442 m; PO-track 7 – 444 m. All existing interim platforms were demolished and two new platforms (250 m long, with a height of 0.55 m above the railhead) have been constructed, and the front platform has been extended with 53 m and 116 m in the direction of Ognyanovo and Plovdiv respectively. Platform canopies on a steel structure have been constructed on the new second and third passenger platforms, and a platform canopy has been constructed on the first passenger platform - over the stairs to the underpass and lift. A square in front of the station, reconstruction of the loading ramp and a ramp for people with reduced mobility have been completed. The existing pedestrian underpass has been preserved and expanded by building new stair exits and installing lifts for passengers with reduced mobility – at the two new platforms and at the front platform; 
The drainage of the railway track between the stations and in the area of the stations has been carried out by installing ditches and making drainages. 
All necessary signage has been installed: mileage and hectometric signs, distance indicators and slope indicators, as well as all signage related to train safety. 
The rail crossings at km 132+592.42 and at km 137+336.40 were dismantled and restored after laying the railway track. 
-    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. 
The new overhead line between Pazardzhik and Ognyanovo stations for each of the two tracks comprises 7 tensioning areas with a length of less than 1400 m, and the total length of the catenary is 17 399 m. 
The new overhead line between Ognyanovo and Stamboliyski  stations for each of the two tracks comprises 8 tensioning areas with a length of less than 1400 m, and the total length of the catenary is 20 042 m. 
The neutral insertion on Track № 1 and Track № 2 at km 121+000 is "a short one", made with the use of Galland section insulators. The disconnectors are 6 with a motor actuation. The feeders are All 240 mm2. Surge arresters have been installed. Both local and remote control of the disconnectors is available. 
The electrical panel board for the remote control of the disconnectors is used for local control of the disconnectors by the railway stations, with or without parallel connection. The panel board provides for remote control by a railway energy dispatcher. The electric power supplied to the disconnectors includes both main power supply and and redundant power supply for the disconnectors of the overhead line.
-    Construction works on large facilities: reconstruction of a bridge at km 127+216.10 between the Pazardzhik and Ognyanovo stations – this facility is a road underpass near Ognyanovo station. It has a clearance of 12 m and a total length of 29.20 m, incl. the wings. The overpasses have a common substructure (concrete foundations) and two separate single span top structures under both tracks – Track 1 and Track 2. Performed reconstruction of a bridge situated between Ognyanovo and Stamboliyski stations at km 135+017.33 on Track № 2 – the existing bridge has a double span, each span of 12.80 m, and has a total length of 37.15 m, incl. the wings, and a new bridge at km 135+032.25 on Track № 1. The then existing steel bridge has been replaced by a new bridge which meets the current requirements for speed and safety. The new bridge has a frame construction with two spans, each of 15.00 m, with brackets of 2.75 m, and has a full length of 35.50 m. It is of the "Integral bridge" type.
 
-    Construction works on small facilities and passages for small animals: the small facilities between Pazardzhik and Ognyanovo stations are 10 in total, and between Ognyanovo and Stamboliyski stations – 18 in total. All of these facilities have been cleaned and repaired according to the design. In the area of Ognyanovo station there is an existing culvert at km 127+892.93, which has been rehabilitated. The waterproofing and longitudinal joints (if any) of all slab structures have been replaced. Two (2) passages for small animals have been completed between the Pazardzhik and Ognyanovo stations; 
-    Construction works on retaining walls: Retaining Wall № 1, 144 m long, from km 128+058 to km 128+202, has been completed at Ognyanovo station, and Retaining Wall № 2, 144 m long, from km 129+005 to km 129+149, has been completed between Ognyanovo and Stamboliyski stations – to reinforce the toe of the embankment of the existing railway station platform and the construction of the new one. The retaining walls are of cantilever type, laid on piles Ø 640 mm in diameter and 5.0 - 6.0 m long, situated over 1.20 m. Retaining Wall № 3 is 66 m long and 4.0 – 4.20 m high, Retaining Wall № 4 is 80.50 m long and 3.80 – 4.20 m high – constructed between Pazardzhik and Ognyanovo stations to reinforce the high-rise embankments before and after the railway overpass at km 127+216.10, on the side of Track 2. The walls are separated into separate tronsoons, each of which is 12 m long, with 2 cm joints in between. 
-   Construction works on the pedestrian passage at km 127+940: the structure of the pedestrian passage is a single span steel frame with a span of 19.80 m and cantilever arms at both ends, each of which is 2.80 m long. Its total length is 25.40 m, and the useful width between the railings is 2.25 m. There are lifts at both staircases. The passage is illuminated and drained. 
-    Construction works on the signalling – underground cable ducts: underground cable ducts have been constructed for all the equipment in the section in accordance with Parts Safety Equipment, Electrification, Telecommunications, and Illumination. The manholes between the cable ducts are two types – solid one - in the station area, and manholes made of prefabricated reinforced concrete elements. A provisional signalling has been made - Phase II Ognyanovo Station, and signalling - provisional situation - Phase I- Stamboliyski station. 
-    Construction works on soundproof screens: soundproof screens have been assembled with pilot foundation, with the walls placed on a precast concrete beam restrained in the foundation grille. The section with a soundproof wall situated on the right and in the direction in which the kilometers increase (Track № 1) begins from km 135+957.75 and intermittently continues to km 138+594.90. On the left and in the direction in which the kilometres increase (Track № 2) it begins from km 137+795.62 and continues to km 138+692.21. The total length of the soundproof screens on the right-hand side and in the direction in which the kilometres increase is 1676.00 m. On the left side, the length in the direction in which the kilometres increase is 904.00m. The soundproof screens are of two different heights - 2.50 m and 3.00 m from the ground level. 
-     Construction works on the rehabilitation of the pedestrian underpass at km 138+115.67 at Stamboliyski station: The pedestrian underpass at Stamboliyski station passes under all railway tracks and connects two town districts. New staircases have been completed to the first, second and third tracks. Three lifts for passengers with reduced mobility have been installed at the exit points to the three platforms. The underpass is lined with tiles. The illumination and drainage of the pedestrian underpass of any accidentally caught water have been completed. 
-    Construction works on the water supply and sewerage system: The following features have been completed at Ognyanovo station: rainwater drainage for draining the rainwater from the platforms and platform canopies through grated drains; collection of condensation from the air-conditioning equipment in the rooms accommodating the communication systems on the first floor of the Reception building; fire safety. Fire water tanks and a pumping station building are situated to the southeast of the Reception building. The construction of the building is traditional solid structure, with reinforced concrete beams, columns and a roof slab. The enclosing walls are made of ceramic lattice bricks. A LOWARA fire pump group has been installed in the building - the group comprises two fire pumps (one operating pump and one standby pump) to maintain the pressure in the fire pipeline. There is an equalizing vessel having a flexible diaphragm situated upstream of the outlet of the pusher from the building. Electric power supply, power system and lighting system have been completed in the building. A water meter chamber has been installed. Two steel tanks with a total capacity of 65.00 cubic meters and a payload of 54.00 cubic meters each have been installed next to the pumping station. The tanks are completed with factory-made insulation and are supported on reinforced concrete foundations. Water for filling the fire water tanks is provided from the existing pipeline. The external fire water pipeline is made of HDPE PN 16 pipes, Ø 110 mm or Ø 90 mm. Two DN80 fire hydrants have been installed on the ground. Each hydrant has a DN80 mm shut-off valve upstream of it. 
The following features have been completed at Stamboliyski station: rainwater drainage for draining the rainwater from the platforms and platform canopies, and grated drains have been installed for draining the rainwater from the two new platforms; draining the rainwater from the pedestrian underpass at km 138+115.67 - drainage gratings and two pushers; fire water pipeline for the Reception building, collection of condensation from the air conditioning equipment in the rooms accommodating  the communication systems on the second floor of the RRC (Route-Relay Centralizations) building; crossing of Ø 250 water pipeline at km 137+552.20 - a new crossing of the water pipeline under the tracks and a new branching off the steel pipeline. The fire pipeline is supplied from an existing pipeline. The new fire water pipeline is made of HDPE pipes, PN 16, Ø 90 mm. 
- Construction works on the illumination: operating and on-duty lighting (external lighting) has been completed at the platforms at the railway stops and stations, illumination using 18 m high mast poles at the stations, with a lift mechanism, spotlights and illumination of railway switches. 
- Construction works on the heating of the railway switches.   
- Construction works on the repair of the rooms accommodating the telecommunication systems at Ognyanovo station and at Stamboliyski station: the necessary conditions for locating the telecommunication systems have been met, the rooms have been repaired and cleaned, power lines and panel boards installed, a power system and a lighting system have been completed, as well as heating, ventilation and air conditioning (HVAC).   
- Construction works on the rehabilitation of power factor correction switchgears owned by the State Enterprise “National Railway Infrastructure Company” and situated at Ognyanovo station and Stamboliyski station - repair and refurbishment of the switchgear buildings: completed repair and refurbishment of the rooms. The following equipment at the switchgear in Ognyanovo owned by the State Enterprise “National Railway Infrastructure Company” has been replaced during the rehabilitation - a new LV panel board, current transformers, automatic circuit breakers, new passive insulators, supporting insulators, surge arresters, a new stand, MV fuses, earthing and lightning protection installations. The switchgear cell is complete with TM 20/04 kV, 160 kVA switchgear equipment and rails of passive insulators to the switchgear equipment itself, RM type breaker and fuses to protect the switchgear equipment. The rehabilitation of the switchgear at Stamboliyski station included replacement of supporting insulators and cable head of incoming cables. The switchgear cell is a separate room. The switchgear equipment is TM 20/04 kV, 400 kVA, dry type.   
- Construction works on the power supply of the Route-Relay Centralizations, underpass at Ognyanovo Railway Station and Pasarela.   
- Track surveying and benchmarking.   
The construction has been completed with very good work organization in accordance with the approved detailed design, relevant regulations and standards, SPA, and the requirements of the Contracting Authority.