Ballastless Track (BLT) in India | Ballastless track system | Rail Track

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Ballastless Track

Ballastless track or slab track is a type of track system construct without using ballast.



We are using mines waste as railway track ballast having various advantages but at a certain limit. like

  • The ballasted track requires a low investment cost.
  • The ballasted track is usually easy to lay.
  • The ballasted track has good drainage performance. 

Good quality track ballast is made of crushed stone

                                


Ballastless Track (BLT) in india

Made of concrete and asphalt that are replacing standard ballast track. Due to the use of concrete it becomes very stiff and brittle. to obtained elasticity we generally provide elastic pad below the rail.



There are two types of concrete are going to using in Rheda 2000.
  1. Precast Sleepers
  2. In situ Concrete 

Precast Sleepers

It is made-up of Semi Pre cast Bi Block sleepers which consist of two blocks linked with each other with two lattice girders. lattice girders prevent relative movement of independent blocks and simultaneously act as reinforcement for the twin blocks.

                             



After steam curing and water curing it achieve compressive strength of 55 MPa in 15 days.

 In-situ Concrete 

In-situ concrete in Ballastless track in Tunnel is being done in three stages as under: -
  1. Plain Cement Concrete (PCC)
  2. Track Concrete Layer (TCL)
  3. Derailing Block (DB)

1. Plain Cement Concrete (PCC)

PCC is placed over the drainage layer (tunnel without invert) or permanent invert concrete (tunnel with invert) at 764 mm below rail level up to 473 mm below rail level. This 291 mm thick M-20 layer acts as a base concrete layer. The PCC is casted in segments of 50 m in length.   

2. TRACK CONCRETE LAYER (TCL)

The ballast-less track in Tunnel T-80 consists of semi pre-cast bi-block RCC Rheda-2000 sleepers manufactured using M-55 Grade Concrete with the lower part of lattice girders projecting outside the concrete body of the sleeper. For rail fixing, dowels which are part of Vossloh fittings are embedded while casting the sleepers. These sleepers are embedded in an RCC layer of 243 mm thickness. This layer is called Track Concrete Layer (TCL) and is of M-35 grade concrete. The TCL consist of two layers of reinforcement with both the bottom and top layer composed of rebars of 16 mm ΓΈ in the longitudinal direction and transverse direction. The track concrete layer is placed over 291 mm thick M 20 grade PCC base layer concrete. The procedure for casting of TCL is explained in the following paragraphs

3. Derailing Block (DB)

The derailment block is laid with the same grade of concrete as in TCL i.e. M-35. Special fabricated shuttering plates (Photo 14) are used for casting of derailment blocks. The derailment block performs the functions of a guard rail on a normal track. The width of the derailing block in the central portion is 1173 mm with a height of 230mm. The clearance of 250mm of derailment block from the gauge face of the rail is maintained. Also, clearance of 180mm is provided on non gauge side of the rail. The clearances are kept such that the sleeper fittings could be removed easily on one hand and road vehicles could move over the track on other hand in case of emergency.

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