RAILWAY SUPERSTRUCTURE

CBG W14 Fastening System

BG W14 fastening system is produced according to BS EN 13481-1, point 3.1.3 (Category C fastening system) and BS EN 13481-2 table 1 (Fastening category criteria), for conventional mainline railways, with a typical axle load of 225 kN (Max. 260 kN), a typical curve radius of 400 m (Min. 150 m), a typical maximum speed of 250 km/h, a typical rail section of 60E1 and a typical sleeper or support spacing of 600 mm.
CBG W14 fastening system is a direct fastening system. The main components of CBG W14

fastening systems are as follow:
– Tension clamps
– Sleeper screws
– Guide plates
– EVA rail seat pads
– Plastic dowels

W14 Tension clamps

CBG W14 tension clamps are used to hold the rail on the concrete sleeper. These components resist the dynamic vertical movements and afford resistance against dynamic and static loads and support the rail tilting protection. The tension clamp provides the fatigue resistance of the fastening system. CBG W14 tension clamps are coated with Dacromet 500. Tension clamps are made of alloy spring steel (e.g. 38Si7/1.5023) according to BS EN 10089.

W14 Sleeper Screw

CBG W14 screws are used to hold the tension clamps and consequently other fastening system components and rail at the correct position on the concrete sleeper. Also, the screw-dowel combination provides the pull-out resistance of the fastening system. CBG W14 screw produced according to UIC 864-1. The screw is manufactured from one piece of steel, without welding. The screw is made of steel according to UIC 864-1 (e.g. Grade 4.6).

W14 Rail Seat Pad

CBG W14 rail seat pads are used to distribute stress and damping of axial forces acting on the sleeper and to insulate the rail. The rail pad ensures that the system bears the traffic loads and reduces noises and damps vibrations. CBG W14 pad produced according to UIC 864-5. CBG W14 rail seat pad is made of virgin Ethylene-Vinyl Acetate (EVA) granules. EVA thermoplastic elastomer virgin granules are supplied from the most prestigious companies worldwide; Dupont, Total, Formosa etc.

W14 Guide Plate

CBG Slab The main aim of using W14 guide plates is to install the tension clamps, creating electric insulation for the rail fastening equipment, lead the forces to the concrete sleeper and support the rail tilting protection. CBG W14 guide plate is made of virgin Polyamide 6/6.6 granules reinforced through injection of glass fibres (30-35% GF). The raw materials for this product are purchased from BASF and Bada Companies.

W14 Dowel

Plastic dowels (cast in parts) are used to anchor and electrically isolate screws inside the concrete sleeper. Dowels are made of high strength Polyolefin (PO). Also, the dowel screw combination provides a sufficient pull-out force according to BS EN 13481-2.

CBG Heavy Haul (CBG HH) Fastening System

CBG Heavy Haul fastening system is designed and produced for heavy-haul tracks. CBG HH fastening system is compliant with BS EN 13481-1 point 3.1.5 (Category E fastening system) and BS EN 13481-2, table 1 (Fastening category criteria), for mixed traffic line carrying heavy freight trains, with a typical axle load of 300 kN (Max. 350 kN), a typical curve radius of 150 m, a typical maximum speed of 200 km/h, a typical rail section of 60E1 and a typical sleeper or support spacing of 600 mm. CBG HH fastening system is a direct fastening system.
CBG HH fastening system tests were carried out in the laboratories of the Mechanical Engineering Department, Politecnico di Milano, in Italy in 2018. According to the results of laboratory tests, the CBG HH fastening system is compliant with BS EN 13481-1 and BS EN 13481-2.

The main components of the CBG HH fastening system are as follow:
HH guide plates
HH rail seat pads
HH tension clamps
Plastic dowels
Sleeper screws

CBG HH Fastening System Characteristics:
Standard: BS EN 13481 (Category E)
Axle Load: Max. 350 kN (35 t)
Speed: Max. 200 km/h
Curve Radius: Min. 150 m
Longitudinal Rail Restraint: ≥ 9 kN (BS EN 13146-1)
Electrical Resistance: ≥ 5 kΩ (BS EN 13146-5)
Change of performance before and after of repeated loading tests:
Clamping force: Change ≤ 20% (BS EN 13146-4)
Longitudinal rail restraint: Change ≤ 20% (BS EN 13146-4)
Vertical static stiffness: Change ≤ 25% (BS EN 13146-4)
Effect of exposure to severe conditions: Without failure in any component

Heavy-Haul Tension clamps

CBG HH tension clamps are used to hold the rail on the heavy-haul concrete sleeper. These components resist the dynamic vertical movements and afford resistance against dynamic and static loads of heavy axle loads. There are two tension clamps on each rail seat in this fastening system to ensure the continually grip rail down.
CBG HH tension clamp is made of alloy spring steel (e.g. 38Si7/1.5023) according to BS EN 10089 (Hot rolled steels for quenched and tempered springs. Technical delivery conditions). CBG HH tension clamps are heat treated (quenched and tempered) to the hardness of 400-460 HV30. These components are coated with Dacromet 500.

Heavy-Haul Sleeper Screw

CBG HH screws are used to hold the HH tension clamps and consequently other fastening system components at the correct position. Sleeper screws are used to secure the rail by fastening the system, to the concrete sleeper. Also, the screw-dowel combination provides the pull-out resistance of the fastening system.
CBG screw produced according to UIC 864-1. The screw is manufactured from one piece of steel, without welding.

Heavy-Haul Rail
Seat Pad

CBG HH rail seat pads are used to distribute stress and damping of axial forces acting on the sleeper and to insulate the rail in CBG heavy-haul fastening system. CBG HH rail seat pad ensures that the system bears the traffic loads and reduces noises and damps vibrations in freight lines. CBG HH rail seat pads produced according to UIC 864-5.
CBG HH rail seat pad is made of virgin Ethylene-Vinyl Acetate (EVA) granules. EVA thermoplastic elastomer virgin granules are supplied from the most prestigious companies worldwide; Dupont, Total, Formosa etc.

Heavy-Haul Guide Plate

CBG HH guide plate is made of virgin Polyamide 6/6.6 granules reinforced through injection of glass fibres (30-35% GF). The raw materials for this product are purchased from BASF and Bada Companies.
The main aim of using HH guide plates is to install the tension clamps, creating electric insulation for the rail fastening equipment, transverse the forces to the concrete sleeper and used for lateral rail guide to secure rails against lateral movement.

Heavy-Haul Dowel

Plastic dowels (cast in parts in HH sleepers) are used to anchor and electrically isolate screws inside the concrete sleeper. Dowels are made of high strength Polyolefin (PO). Also, the dowel-screw combination provides a sufficient pull-out force according to BS EN 13481-2.

Ballast

Ballast is a type of crushed stone which are used in the construction of the upper layer of railway track. Track ballast forms the trackbed upon which railroad sleepers are laid. The ballast also holds the track in place as the trains roll over it which is used to bear the load from the railroad sleepers, to facilitate drainage of water, maintain the track’s stiffness and also to keep down plants that might interfere with the track structure.
CBG’s ballast is made of clean, 100% crushed high-quality white granite stones. This ballast is produced at the Pariz stone crusher plant and meets the ballast specifications for the railway. this product was used in Bafq-BandarAbbas and other projects.

Sub-ballast

Track ballast typically rests on a layer of smaller crushed stones which is called the sub-ballast. The sub-ballast layer gives a compact support for the top ballast layer, and decreases the entrance of water from the underlying sub-grade.
CBG produces crushed granite sub-ballast for superstructure projects. This product is produced at Pariz stone crushing plant and meets the sub-ballast specifications for railway. this product was used in Bafq-BandarAbbas and other projects.

Aggregates

CBG Company has developed an integrated logistic chain of mine, crusher equipment, transportation and quality assurance system that allows it to supply the aggregates for its own concrete products. CBG produces a full range of concrete coarse and fine aggregates in Sirjan and Shahroud aggregates crushing plants. Our crushing plants in Sirjan and Shahroud provide high-quality sand and gravel aggregates for our concrete products which reassure the reliability of our products.

Ballast distribution
(First Layer)

The first layer of ballast contains of a well graded crushed rock and provides a uniform layer. This ballast layer must have sufficient depth and width. Distribution of this layer is done by special trucks and machineries.

Assembling track panel

CBG track panels are short parts of railway track which are preassembled in the factory or construction site in order to ensure accuracy, precision and faster progress of projects. CBG company is able to transfer track panels by rail to construction site for fast and more convenient installation.

Surveying

According to the track-laying method, before starting the track installing operation, surveying and nailing is done along the track.
CBG company has experienced and trained personnel who are specialized in mapping and surveying railway superstructure.

Track panel laying

Track installation is done manually or mechanized. In the mechanized method, the track panels are transported to the construction site by using special wagons and then installed by special rail-laying machines.
CBG company has 5 self-propelled cranes including two Kirow railway cranes, one TAKRAF crane and two УК-25/25 track cranes which are multi-purpose machinery for track, switch and bridge construction.

Track adjustment

After implementing the track panels, the track is adjusted by railway construction machines. CBG is the only private section company in Iran that has a complete set of special track-laying machinery including railroad cranes, tamping machines, switch tamping machines, ballast distributors, stabilizers, wagons and locomotives.
At first, the ballast pouring is performed by ballast transport wagons, which is produced in accordance with UIC standards. With these wagons, ballast pouring can be carried out over a longer distance at a shorter time. After this step, the ballast is distributed and profiled by using the Plasser & Theurer USP-403 ballast distributor which is a high capacity ballast distributing and profiling machine with shoulder ploughs, ballast hopper and one sweeper unit with transverse conveyor belt for plain track and turnouts.
Subsequently, the tamping operation is performed by the Plasser & Theurer 08-32 in order to align the line. This operation involves levelling, lifting, lining, tamping and adjusting the track.
After tamping, the Plasser & Theurer DGS 62 N stabilizer is used to Homogenization of the ballast bed which ensures quality and sustainability of the track.
In the end, by using the graphs which are prepared by tamping machines, if necessary, the whole process will be performed again for the 2nd time.

Laying railway switches

CBG company performs replacement, assembly, installation, tamping and welding of switches. Switch assembly is done at the construction site. After installing the switch, the switch tamping operation is performed by Plasser & Theurer 08-475 UNIMAT 4S. CBG is the only owner of switches tamping machine in Iran. With the Unimat 08-475/4S, the entire switch system is treated in the technologically correct way and fixed immediately in the accurate position by full tamping.
Welding of switch, due to its special geometry, different material and different rail profiles is a special activity. The CBG’s switches welding personnel and inspectors are trained and approved by the German company Elektro-Thermit.

Rail joint welding

After adjusting and stabilizing the track, the welding operation of the rails is performed using the methods of Enclosed Arc Welding (EAW), Alumino Thermic and Flash Butt Welding.
Welding and joining rails are considered as one of the specialized works in railway superstructure projects; therefore, all the CBG welders are trained and certified by the railway authority. Also, welding inspectors are approved and authorized to carry out weld inspections as well as CBG switch welders and inspectors who are trained and approved by the German company Elektro-Thermit.

Final track adjustment

After the welding operation, if necessary, ballast re-casting is performed and then the final adjustment of the track is accomplished. At this stage, the final tamping is performed using the Plasser & Theurer 09-32 CSM tamping machine. 09-32 CSM tamping machine is a high performance and precise machine for levelling, lifting, aligning and tamping of the track.

Ballastless track (Slab track)

A ballastless track or slab track is the other type of railway superstructure. In this type, a combination of ballast and sleepers is replaced by a rigid bed. Ballastless track provides many advantages compared to ballasted track. Slab track provides higher stability with a uniform and integrated stiffness along the track. Therefore, the slab track is more suitable for high-speed lines. It is also used in tunnels, light rail transit systems, over bridge decks, in railway stations and corridors. Moreover, slab track has significant lesser maintenance costs compared to ballasted tracks.
CBG was the first company to manufacture concrete slab tracks in Iran and so far, the company has produced more than 13,000 slab tracks. CBG’s slab track is a prestressed and pre-fabricated concrete component in which the structure supporting the rails and transmitting the track forces into the sub-base. Also, there is a rubber mat is located below the concrete slab track. This mat increases the resilience of the track, which results in noise and vibration reduction.