Process and system for laying tracks for underground, railway and tramway lines

Abstract

The present invention relates to a process and to a system for laying tracks for ballastless railway and tramway lines, both in tunnel and in surface.

1 . A prefabricated slab for implementing layouts of ballastless railway and tramway lines, with substantially rectangular shape, with a longitudinal direction (L) corresponding to the direction (B) of laying tracks, and a transverse direction (T) orthogonal thereto, made of prestressed concrete both in the longitudinal direction (L) and in the transverse direction (T) by means of a primary reinforcement implemented with post-tensioned, sheathed wires, anchored at respective threaded ends (P) by means of metal plates and locking nuts,
 said slab further comprising a loose reinforcement, consisting of bars arranged to form a mesh embedded in cement,   said slab having a thickness varying, depending upon the longitudinal and transverse sections, between about 200 mm and about 240 mm.   
     
     
         2 . The prefabricated slab according to  claim 1 , wherein said onboard loose reinforcement bars have a diameter of about 8 mm. 
     
     
         3 . The prefabricated slab according to  claim 1 , wherein said primary reinforcement and loose reinforcement are made of non-metallic materials. 
     
     
         4 . The prefabricated slab according to  claim 1 , wherein the external sizes of a slab are about 2.45 m×4.75 m. 
     
     
         5 . The prefabricated slab according to  claim 1 , further comprising at least a through-hole from the extrados to the intrados, with diameter of about 105 mm, for casting the underlying intermediate layer. 
     
     
         6 . The prefabricated slab according to  claim 1 , further comprising at a compartment, open to the intrados, along the longitudinal axis of the slab for housing corresponding horizontal stabilizing elements. 
     
     
         7 . The prefabricated slab according to  claim 6 , comprising two compartments for housing corresponding horizontal stabilizing elements, each one with sizes of about 278×345 mm, at the second and penultimate spacing of the slab. 
     
     
         8 . The prefabricated slab according to  claim 1 , comprising a plurality of through-compartments from the extrados to the intrados for housing corresponding supporting devices each one comprising a mechanical device allowing to adjust the plano-altimetric position of the slab. 
     
     
         9 . The prefabricated slab according to  claim 8 , comprising fourteen through-compartments, 3+3 thereof positioned at about 190 mm from the longitudinal side edges of the slab and additional 4+4 at about 660 mm from said longitudinal side edges. 
     
     
         10 . The prefabricated slab according to  claim 8 , wherein said each supporting device comprises a screw M39 which transfers the load to a resting plane through a distribution plate and a steel plate, with sizes of about 160×160 mm and thickness of about 15 mm to support the slab. 
     
     
         11 . The prefabricated slab according to  claim 1 , wherein the intrados surface of the slab is treated with a product having high penetrating power, applied directly on the concrete surface by making it not adherent to the products thereof the intermediate layer is made and by protecting the concrete from degradation phenomena, creating a hydrophobic effect which drastically reduces the absorption of water and chlorides by preventing the corrosion of the reinforcing rails. 
     
     
         12 . The prefabricated slab according to  claim 1 , comprising a strap made of thermoplastic elastomer fastened in the separation area between slab and on-site casting. 
     
     
         13 . The prefabricated slab according to  claim 1 , comprising a trapezoidal profile ( 30 ) applied to the side walls to be extracted before the removal of the prefabricated element. 
     
     
         14 . The prefabricated slab according to  claim 1 , comprising an elastomeric mat fastened on the intrados surface, with thickness optionally from 6 mm to 25 mm. 
     
     
         15 . The prefabricated slab according to  claim 1 , comprising an additional mass made integral with the slab, optionally implemented by one or more concrete plates. 
     
     
         16 . A system for laying tracks for ballastless railway and tramway lines on prefabricated slabs, comprising:
 a train for launching the slabs, equipped with handling portal and wagon for end-on launching the slabs; and   a concreting train equipped for the production of concrete and for casting an intermediate or foundation layer, supporting the slabs.   
     
     
         17 . The system according to  claim 16 , wherein said prefabricated slabs have substantially rectangular shape, with a longitudinal direction (L) corresponding to the direction (B) of laying tracks, and a transverse direction (T) orthogonal thereto, made of prestressed concrete both in the longitudinal direction (L) and in the transverse direction (T) by means of a primary reinforcement implemented with post-tensioned, sheathed wires, anchored at respective threaded ends (P) by means of metal plates and locking nuts, said slabs further comprising a loose reinforcement, consisting of bars arranged to form a mesh embedded in cement, and said slabs having a thickness varying, depending upon the longitudinal and transverse sections, between about 200 mm and about 240 mm. 
     
     
         18 . The system according to  claim 16 , wherein said train for launching the slabs comprises flat wagons whereon the slabs are placed. 
     
     
         19 . The system according to  claim 18 , wherein said train for launching the slabs comprises a mobile portal for handling the slabs, from the flat wagon to a gripping point of the launching wagon. 
     
     
         20 . The system according to  claim 16 , wherein said train for launching the slabs comprises a crane system for positioning the slabs in the railway seat. 
     
     
         21 . The system according to  claim 16 , further comprising a train equipped for the removal and loading of spans of pre-existing track. 
     
     
         22 . The system according to  claim 16 , further comprising a train for excavating and removing a pre-existing ballast. 
     
     
         23 . A process for laying tracks for ballastless railway and tramway lines on prefabricated slabs according to  claim 1 , comprising the following steps:
 launching of the slabs and laying thereof in sequence on a platform plane, said slabs being laid with pre-installed temporary rails;   plano-altimetric adjustment of each launched slab, by comparison with topographic references pre-installed along the railway and tramway line;   junction of said temporary rails to form continuous temporary tracks;   casting of an intermediate or foundation concrete layer between the intrados surface of the slabs and said platform plane;   removal of said temporary tracks;   installation of definitive rail tracts; and   welding of said definitive rail tracts to form definitive tracks.   
     
     
         24 . The process according to  claim 23 , further comprising a step of removing pre-existing tracks. 
     
     
         25 . The process according to  claim 23 , further comprising a step of excavating a pre-existing ballast, as far as a platform plane. 
     
     
         26 . The process according to  claim 23 , wherein the laying of rails is performed so that said temporary junctions of the rails result to be at the centre of the first spacing of each slab. 
     
     
         27 . The process according to  claim 23 , wherein said temporary junctions are of the rested type and implemented with four-hole jaws. 
     
     
         28 . The process according to  claim 23 , comprising a step of arranging horizontal stabilizing elements below each slab to be laid, preceding the step of casting the intermediate layer, so that said horizontal stabilizing elements result at least partially embedded in the intermediate layer. 
     
     
         29 . The process according to  claim 23 , wherein the concrete of said intermediate layer has a composition so as to guarantee a workability of at least thirty minutes, and development of short-term resistances, preferably a resistance equal to at least 5 MPa within two hours from casting. 
     
     
         30 . The process according to  claim 23 , comprising a step of implementing transition areas between ballastless permanent way and ballasted permanent way to obtain a maximum variation of the vertical settlement not higher than 0.5 mm, and/or and a tamping connecting between the laid tract and the existing track. 
     
     
         31 . The process according to  claim 23 , performed with a system comprising:
 a train for launching the slabs, equipped with handling portal and wagon for end-on launching the slabs; and a concreting train equipped for the production of concrete and for casting an intermediate or foundation layer, supporting the slabs.