EP4159921A1 - Method and train for replacing rails - Google Patents

Abstract

In the method, for each row of rails, the following steps are carried out: (1) a new rail is taken from new rail transport cars containing a plurality of new rails arranged on roller supports allowing them to move freely in the longitudinal direction; (2) the new rail is moved by guiding it with guide means and it is placed on rollers previously placed on the ground between the sleepers of the rails to be replaced; (3) it is welded end-to-end said new rail to a new rail, previously laid, with a welding train;(4) the welding train is moved so that the new welded rail is unloaded from the transport wagons by sliding on roller supports and on the means guide;(5) during the movement of the welding train, taking a new rail of the plurality of new rails and bringing it close to the free end of the welded rail being unloaded;(6) performing steps (2) through (5) repeatedly to reach the predetermined number of new welded rails in succession;(7) releasing the new welded rails by heating to a release temperature;(8) ) replaces the old rails with the new rails welded and released by fixing them at their release temperature;(9) the old replaced rails are evacuated. The application also relates to a device for implementing this method.

Description

TECHNICAL AREA

The present invention relates to the field of maintenance of railway tracks. More specifically, the present invention relates to the field of replacing worn rails of a railway track with new rails.

STATE OF THE ART

• -) approvisionnement de barres plus ou moins longues d'environ 108 mètres à 300 mètres, préalablement réalisées dans des ateliers de soudage éloignés du chantier à partir de rails élémentaires d'environ 80 mètres et plus rarement 120 à 150 mètres provenant des usines de fabrication de rails et mise en place sur la voie ferrée, par exemple entre les rails à remplacer,
• -) enlèvement des attaches et tronçonnage des rails usés,
• -) enlèvement des rails usés,
• -) mise en place des barres longues neuves,
• -) soudure alumino-thermique des barres longues entre elles,
• -) fixation des rails neufs sur les traverses,
• -) raccordement des rails neufs à la ligne existante par soudure alumino-thermique,
• -) libération des contraintes (desserrage des attaches des rails neufs, frappe et étirement des rails, resserrage des attaches),
• -) rechargement des rails usés, et
• -) nettoyage du chantier.

Such substitution of rails is typically carried out at night on a determined section of a railway line by a rail substitution train. The principle of the method consists in replacing the worn rails with new rails without intervening on the other elements of the track (platform, ballast, sleepers). A known method includes the implementation of the following steps:

• -) supply of more or less long bars of approximately 108 meters to 300 meters, previously produced in welding workshops far from the site from elementary rails of approximately 80 meters and more rarely 120 to 150 meters from manufacturing plants of rails and installation on the track, for example between the rails to be replaced,
• -) removal of fasteners and cutting of worn rails,
• -) removal of worn rails,
• -) installation of new long bars,
• -) alumino-thermal welding of the long bars together,
• -) fixing new rails on the sleepers,
• -) connection of the new rails to the existing line by alumino-thermal welding,
• -) release of constraints (loosening of fasteners of new rails, hitting and stretching of rails, tightening of fasteners),
• -) reloading worn rails, and
• -) cleaning of the construction site.

Trains and rail substitution methods are known in the state of the art. For example posting FR 2 904 335 describes such a train and such a method of replacing rails on a high-speed line. More specifically, in this publication, the method described relates to a process for replacing the rails of a high-speed line in which the new single rails are transported directly to the renewal site by wagons forming part of the works train. Two rows of three rails are unloaded onto rollers between the rows of rails to be replaced and the three rails of each row are assembled on site into long bars by spark-forging. For this purpose, a welding machine is engaged in the substitution area and carries out two welds on each line of new single rails to assemble the three rails into a single long bar, i.e. two bars approximately 360 meters long waiting between the two lines. worn rails. Simultaneously with the replacement of the worn rail sections with new long bars, the said long bars are freed by induction heating at a temperature between 25°C and 32°C, put in place and immediately fixed, the connection of the new rails to those of the existing track being carried out by means of alumino-thermal welding. The worn rail sections are immediately reloaded onto wagons forming part of the works train, and at the end of the shift, the works train is released from the site to allow the track to be restored with running capacity at normal commercial speed.

• -) les nouveaux rails, préalablement acheminés sur le chantier, sont chauffés en continu afin d'être neutralisés, les rails étant à cet effet soulevés et exposés à une source de chaleur déplacée de façon continue,
• -) les anciens rails sont détachés des traverses et déposés le long de la voie ou évacués,
• -) les nouveaux rails amenés et maintenus à la température de neutralisation sont posés en continu sur les traverses et y sont attachés. L'avantage essentiel de ce procédé est de permettre, en un seul processus, à la fois la substitution et la neutralisation des rails, et cela de manière mécanisée, ce qui procure de considérables gains de temps et de main-d'œuvre.

Another method and another device for the substitution and " neutralization " (for this neutralization operation the equivalent term of " release " is also used, the two terms having the same meaning in the present application) of the rails of a track railway are known from the publication EP 0 466 651 . To achieve this goal, the method according to EP 0 466 651 is characterized in that:

• -) the new rails, previously transported to the site, are continuously heated in order to be neutralized, the rails being for this purpose raised and exposed to a source of heat moved continuously,
• -) the old rails are detached from the sleepers and deposited along the track or evacuated,
• -) the new rails brought and maintained at the neutralization temperature are laid continuously on the sleepers and are attached to them. The essential advantage of this process is to allow, in a single process, both the substitution and the neutralization of the rails, and this in a mechanized way, which provides considerable savings in time and labour.

Other benefits of the publication process EP 0 466 651 result from the fact that the heating operation can be done easily by high frequency induction and takes place continuously, while the new rails to be heated are not at all housed in the fasteners of the sleepers. Thus freed from the track, the new rails can be more easily exposed to the heat source. The continuous heating system proposed also has the advantage of not requiring longitudinal transport of the treated rails: it is the replacement train that advances, while the new rails are only raised.

The heating as well as the temperature of the treated rails can respectively be controlled and measured much more easily and more accurately than on the open track according to current non-mechanized systems. Another advantage of the publication process EP 0 466 651 is that during the heating of the new rails, the old rails are detached and released, which again saves time.

The publication EP 0 835 712 describes a process for welding at least one line of new railway rails to replace the old rails, previously laid down on the track, by means of a machine running on the old rails, the machine being provided in particular with a welder by spark-forging, grinding means and gripping and guiding means for the new rails.

The publication EP 0 551 798 describes a device for the continuous substitution and neutralization of railway tracks. In this device, the articulated vehicle serves to substitute and neutralize the rails of the railway tracks while it advances in the direction of the arrow at a constant continuous speed. For this purpose, it is equipped with medium frequency induction heating tunnels to continuously heat the new rails to their neutralization temperature; this temperature which they must have during their attachment to the sleepers generally being around 25° C. The new rails are first brought to the site, placed in the middle of the old track between the old rails and welded to form two continuous rows of rails. These rows of rails are lifted and guided through the heating tunnels as the vehicle advances. For the substitution, the vehicle further comprises workstations making it possible respectively to detach and attach the fasteners of the old and new rails.

SUMMARY OF THE INVENTION

An object of the invention is to propose a method and a device considerably improving the known methods and devices, in particular those known from the publications FR 2 904 335 , EP 0 466 651 , EP 0 835 712 And EP 0 551 798 .

Another object of the present invention is to provide a method and a device by means of which the occupation time of the track is reduced to a minimum.

Another object of the present invention is to propose a method and a device by means of which the efficiency of the machines is optimized and the losses of time reduced or eliminated.

In the present invention, the known method of FR 2 904 335 in that the feeding of new rails is carried out not from the ground with individual rails previously deposited on the ground and assembled into long bars by welding, which involves additional operations and a loss of time, but by new rails supplied continuously from a single rail supply machine. Consequently, the provision of the new rails is not the subject of a specific and/or prior operation (for example the day before or just before the replacement work begins on the site) but on the contrary this supply is carried out directly and gradually in an operation integrated into the general process of replacing the track.

An advantage of this way of proceeding is the simplification of the general process because it is not necessary to independently manage the stock of new rails: this is an integral part of the replacement train.

Another advantage is the time saving due to the elimination of a dedicated and preliminary operation for the temporary storage of the new rails on the track in anticipation of the substitution and their welding in long bars as described in FR 2 904 335 . Compared to the known method of this publication, the present invention provides a gain of approximately two hours.

Another advantage of the present invention is that personnel are better protected due to the automation of the process steps.

Another advantage of the present invention is that after the substitution, the track allows traffic to travel at commercial speed.

The invention is defined by the independent claims and particular embodiments thereof are covered by the dependent claims.

Other characteristics and advantages of the present invention are detailed below in the description of the embodiments of the invention and the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

• There figure 1 generally illustrates a rail substitution train according to the invention.
• There picture 2 schematically illustrates the parts forming the train according to the present invention.
• There picture 3 illustrates in more detail an embodiment of the welding train according to the present invention.
• There figure 4 illustrates a mode of execution of the means of supplying new rails.
• There figure 5 illustrates a mode of execution of the supports for new rails on the transport wagons of said rails.
• THE figures 6A to 6E illustrate embodiments of the guide means used to support the new rails.
• There figure 7 illustrates an embodiment of the rear part of the welding train.
• THE figures 8A to 8C illustrate the deburring of a shoe of a welded rail.
• There figure 9 illustrates a mode of execution of the train of substitution and release of the rails.
• There figure 10 illustrates a mode of execution of the old rail recovery train.

DETAILED DESCRIPTION

According to the invention, all of the means of production is formed of a single construction train 10 which is transported in a single block on the construction site (known as a "block train"), see the figure 1 which also shows the working direction of said train.

In transport configuration, the construction train with all its components is approximately 515 m long.

• -) la mise à disposition des nouveaux rails sur le chantier et la fabrication des longs rails soudés par un train de soudage 100 qui comprend l'approvisionnement et le soudage des nouveaux rails;
• -) la substitution et la libération des nouveaux rails par un train de substitution et de libération des nouveaux rails 200; et
• -) le chargement des anciens rails par un train de chargement des anciens rails 300.

As soon as it arrives at the site, the unit train 10 is split into three distinct parts 100, 200, 300 (see figure 2 ) which evolve independently during the works. Each part performs a specific operation or set of operations:

• -) the provision of new rails on the site and the manufacture of the long rails welded by a welding train 100 which includes the supply and welding of the new rails;
• -) the substitution and release of the new rails by a train of substitution and release of the new rails 200; And
• -) the loading of the old rails by a loading train of the old rails 300.

These parts generally represented in the figure 2 are detailed below.

There picture 3 illustrates in detail the welding train 100 of the new rails. This train 100 comprises in particular a traction device 110, wagons 120 for transporting new rails 20 (normally the train comprises six transport wagons 120 forming a storage train but the picture 3 represents only one with a section for simplicity), a gantry 130 moving on a transport wagon 129 of the gantry and on the wagons 120 for transporting the new rails, and a welding machine 140, 150 for welding the new rails and carrying in particular a welding head 151.

There figure 4 illustrates in detail the six transport wagons 120 of new rails and the gantry 130 on its wagon 129.

The new rails 20 are loaded at the rear base on a dedicated composition, consisting for example of six rail transport wagons 120 provided with a rolling path for the gantry 130. The gantry 130 for handling the rails is capable of moving on its 129 transport wagon and the (six) 120 transport wagons of the new 20 rails.

The transport wagons 120 are equipped with a track for the gantry 130 with removable connecting rails which are brought into working position by means of a remote control.

The storage of the new rails 20 is illustrated in figure 5 (in front view). Each new unitary rail 20 is stored in each wagon 120 on a set of rollers 30 which ensure a longitudinal path of each new rail 20 without resistance. The configuration of the rollers 30 notably guarantees the result of the release by heating. This figure 5 illustrates a full stock of thirty new rails 20 but of course this is an illustrative example and the number of rails may be more or less than thirty. During the transport phase, a mechanism stows and secures the rails 20 on the wagons 120. A remote control allows the unlocking of this device.

The handling gantry 130 is equipped with independent traction and two arms 131 fitted with grippers capable of gripping two new rails 20 (i.e. one new rail 20 per row) without damaging them and inserting them into a loading device between the rows of rails of the track. Portico 130 is, for example, provided with a secure driver's cabin comprising two workstations and all the tasks are carried out from the cabin.

In the working phase, the transport wagon 129 of the gantry 130 ensures the guidance of the rails between the transport wagons 120 and the welding machine 150.

At the front of the machine 100, the handling gantry 130 picks up a pair of new rails 20 using two independent grippers on its arms 131. By convention in the present application, each new rail extracted from stock is identified by the reference 21 once it has passed the reference point 133 in the figures which is located at the beginning of the wagon 129 of the gantry 130. The gantry 130 then introduces each rail 21 on the wagon 129. Each rail 21 is led in guides which hold it in the working jig and which allow them to be placed on the ground on the rolls deposited previously through a chute for loading the rails on the rolls deposited. These guides are provided with rollers allowing free longitudinal movement of each rail 21. The figures 6A to 6E illustrate the rollers 31-36 incorporated in the welding train and implemented for this guidance following each other, starting from the wagon 129 of the gantry, point 133, to the laying on rollers 36, 36 'themselves same placed on the ground between the sleepers in the center of the track before welding, at point D (see figure 7 ). More precisely the roller 31 presses on the head of the rail 21 and the rollers 32 guide the shoe of the rail 21, the roller 33 with edges makes a lateral guide of the shoe of the rail 21, the vertical rollers 34 and 35 of the lateral guides and the roller 35' a guide under the slider of rail 21.

A robotic device, associated with an automated storage system, places the rollers 36, 36' between the sleepers, in the center of the track. These rollers 36 are intended to receive the rails 21 at point D and which will be welded to the rear of the welding machine.

All the rollers (see the figure 6A to 6E ) arranged from the wagons 120 of new rails to the ground (point D) form a continuous guide, without friction, which guarantees the unconstrained path of the rails during the phases of loading, welding and release by heating. Furthermore, robotized installation of rollers 36, 36' eliminates manual operations on the ground.

Beforehand, an automatic system will have placed the rollers 36, 36' between the sleepers in the center of the track. The purpose of these rollers is to ensure the longitudinal floating of the rails from the position where the welding is carried out to the wagons 120 transporting the new rails, which allows the expansion, caused by the welding and the release, to be reflected without constraint. The fact that the new rails 21 are arranged on these supports 36,36' also has the advantage of facilitating the entry and processing of the rails 21, in particular in curves, both for welding and for introduction into the machine. substitution and release.

The welding train comprises a wagon 140 for guiding the new rails 21 and for depositing the rollers 36, 36' on the ground which is described with reference to figure 7 . The guides in this wagon 140 correspond to the figures 6A to 6E as described above. In this figure 7 , the bottom drawing illustrates the track seen from above, on the left the two outer rails being the new rails 21 moved by the gantry 130 after point 133, the two inner rails being the old rails 25 intended to be replaced and on which the train is rolling. As seen on the figure 7 looking from left to right, on the far left (point 133) the new rails are on the gantry car 130 and located above track 25, shown with a gauge greater than that of the track, while that on the far right, the new rails 21 are laid on the ground, on the rollers 36,36' inside the track 25. The laying on the ground of the new rails 21 occurs approximately in the zone D marked in there figure 7 for example at the level of the roller referenced 36' (identical to the rollers 36) through a chute 142.

Generally according to the principles of the present invention, the rolls 36 intended to be placed on the ground are distributed from the wagon 140, which includes a magazine for such rolls 36, and placed on the ground preferably at regular intervals between the crosspieces at the center of the lane. To this end, the wagon 140 includes a distributor 141 of rolls 36 which deposits them on the ground before they receive the new rail 21 in position D ( figure 7 ).

• le wagon 140 décrit ci-dessus et
• une machine de soudage par étincelage-forgeage 150.

Welding machine 140-150 then continuously produces a pair of long welded rails directly from the rail carriers. It consists of two main elements:

• the car 140 described above and
• a 150 flash-forge welding machine.

Depending on the configuration of the site, the two machine parts 140-150 can work together or separately. The rail supply machine ensures the transfer of the new rails 20 from the transport train 120 and their direct introduction into the welding machine 150.

• une tête de soudage 151 par étincelage-forgeage et son unité de contrôle
• un ensemble de pinces de guidage
• un groupe de pinces de maintien lors du soudage
• une paire de bras munis de pinces de manipulation du rail à l'arrière de la machine
• une cabine de conduite.

The welding machine 150 includes

• a flash-forge welding head 151 and its control unit
• a set of guide clamps
• a group of holding clamps during welding
• a pair of arms fitted with rail handling clamps at the rear of the machine
• a driver's cab.

By convention in the present application, the new rails are identified once welded by the reference 22.

Holding clamps grasp the pairs of rails to be welded: the rails 21, on the one hand, the long welded rails 22 placed on the rollers at the axis of the track, on the other hand. The holding clamps precisely orient face to face the ends of the rails 21 to be welded, both in straightening and in leveling. They play a role in the geometric quality of the weld obtained, independently of the layout conditions (curves and slopes).

The method of welding the new rails implemented in the present application is that described for example in the publications FR 2 904 335 , EP 0 466 651 , EP 0 835 712 And EP 0 551 798 mentioned above and reference is made thereto.

The welding machine 150 further comprises at the rear a first handling arm 152 which makes it possible to grasp the welded rails 22 and to move them if necessary.

The welding machine according to the present invention comprises means for deburring the shoe of the rail 22. The deburring is carried out by an automatic device which grinds the side edges and the upper surfaces of the shoe after the welding operation before laying of the welded rail 22 to the ground. During all the welding and deburring operations, the longitudinal axes of the rails 22 are free in order to allow the expansion of the rail for the releasing operation.

THE figures 8A to 8C illustrate an embodiment of deburring according to the present invention, the deburring means being mounted on workbenches of the welding head 151. More specifically, the figure 8A illustrates the deburring of the top of the shoe 23 of the welded rail 22, the figure 8B the deburring of the edges of the shoe 23 of the welded rail 22 and the Fig. 8C deburring the underside of the shoe 23 of the welded rail 22. Suitable grinding wheels 24 are implemented for this operation.

After the new rail 22 of each row has been welded, the welding train 110 - 150 is moved in the working direction (see the arrow pointing to the left in THE figure 3 And 7 For example). During this movement, the new welded rail 220 of each file (which extends onto the cars 120) slides on the rollers 30 of at least two cars 120 and is guided in the cars 129 and 140 as described above.

The gantry 130 then picks up a new free rail 20 for each row, brings it close to the free end of the new rail 22 which has been welded and moves it so that it follows this free end while the welding train 100 moves in the direction of work. It is therefore not necessary to attach a splice between these rails, which saves time. The new free rail 21 is placed on the ground on the rollers 36,36' following the new welded rail 22 and (as illustrated in figure 7 ) the welding operation can be implemented between the end of the new welded rail 22 and the new free rail 21 which follows it directly. These operations are of course carried out for each lane of the track in parallel.

According to the principles of the present invention, the direct feeding of the new rails 20 from the wagons 120 carrying said new rails 20 is very advantageous because it greatly simplifies the process and saves time.

Once the welding is done and in the rest of the process, we proceed to the substitution and release of the new rails 22. The train of substitution and release of the new rails is described for example in the publications identified above FR 2 904 335 , EP 0 835 712 , EP 0 835 712 , EP 0 551 798 And EP 0 835 712 and reference is made to these publications.

• récupération des rouleaux 36 posés au centre de la voie
• desserrage des attaches/ déclipage
• récupération et évacuation des anciennes attaches
• chauffage des nouveaux rails à la température neutre
• dépose des anciens rails
• substitution de semelles élastiques
• pose des nouveaux rails
• montage des nouvelles attaches
• graissage des filets des cames/ boulons à came
• graissage automatique des attaches
• serrage/ clipage des nouvelles attaches
• décalaminage du rail
• contrôle de la géométrie de la voie après remplacement des rails
• graissage automatique du flanc du rail
• manutention des rails (fin d'étape)

The machine 200 for substitution and release by heating of the rails is illustrated schematically in figure 8 (the bottom part of the figure 8 illustrates the track seen from above) and performs the following tasks, continuously:

• recovery of 36 rollers placed in the center of the track
• loosening the fasteners/ unclipping
• recovery and disposal of old fasteners
• heating of new rails to neutral temperature
• removal of old rails
• substitution of elastic soles
• lay new rails
• fitting new fasteners
• lubricate cam threads/cam bolts
• automatic greasing of attachments
• tightening / clipping of new fasteners
• rail descaling
• control of track geometry after replacement of rails
• automatic lubrication of the side of the rail
• rail handling (end of stage)

All of these operations are carried out at a cruising speed of 300 m/h, which can reach 400 m/h in optimal conditions.

The machine 200 includes storage areas adapted and capable of receiving the track material necessary for carrying out the stage. In particular, sufficient space is provided in the rear part for new and used fastening material. Side doors provide easy access and facilitate the loading and unloading of equipment, carried out at the rear base.

A robotic arm 202, positioned at the front of the machine, recovers the rolls 36 which are on the way and arranges them in a storage system. This development therefore eliminates any manual operation requiring the presence of employees on the track between the two machines and thus improves safety.

Arms 201 provided with guide clamps and positioned at the front of the machine ensure, if necessary, the handling of the new rails 22 from the center to the outside of the track, or vice versa.

• reprise manuelle des ratés de serrage
• coupe éventuelle des rails à la longueur en vue de leur chargement
• récupération de pièces.

Behind the machine, a dedicated area is provided for carrying out the following operations if necessary:

• manual recovery of mis-tightening
• possible cutting of the rails to length for loading
• parts recovery.

• un portique de manutention des rails 302 qui reprend les anciens rails;
• un système de stockage des rails sur rouleaux et son dispositif de verrouillage commandé à distance;
• des rails de liaison avec mise en position commandée à distance;
• une motorisation.

A transport train of old 300 rails is positioned at the rear of the machine shown in figure 10 . It includes dedicated 301 rail transport wagons as well as a 302 handling gantry transport wagon. It incorporates the technical characteristics of the new 120-130 rail transport train:

• a rail handling gantry 302 which takes up the old rails;
• a roller rail storage system and its remote-controlled locking device;
• connecting rails with remote-controlled positioning;
• a motorization.

The 300 train is able to transport rails up to 150 m long.

After the complete train has passed, the track can be put back into commercial operation at line speed and up to 300 km/h.

The embodiments described in the present application are by way of illustrative examples and should not be considered as limiting. Other embodiments may make use of means equivalent to those described for example. The modes of execution can also be combined with each other depending on the circumstances, or means used in one mode can be used in another mode.

Claims (13)

Method of replacing railway rails in which the worn rails of two rows forming the track are replaced by new rails, method in which, for each row of rails, the following steps are carried out: (1) a new rail (20) is taken from transport wagons (120) of new rails (20) containing a plurality of new rails (20) arranged on roller bearings (30) allowing them to move freely in the longitudinal direction; (2) the new rail (21) is moved by guiding it with guide means (31,32,33,34,35, 35') and it is placed on rollers (36, 36') previously placed on the ground between the sleepers of the rails to be replaced (25); (3) said new rail (21) is welded end-to-end to a new rail (21), previously placed on the rollers (36,36'), with a welding train (140,150); (4) the welding train (140,150) is moved so that the new welded rail (22) is unloaded from the transport wagons by sliding on the roller supports (30) and on the guide means (31-35') ; (5) during the movement of the welding train, taking a new rail (20) of the plurality of new rails (20) and bringing it close to the free end of the welded rail (22) in the process of to be unloaded; (6) performing steps (2) to (5) repeatedly to reach the predetermined number of new rails (22) welded one after the other; (7) releasing the new welded rails (22) by heating to a release temperature; (8) replaces the old rails (21) with the new welded and released rails (22) by setting them at their release temperature; (9) the old rails (21) replaced are evacuated. Method according to claim 1, in which rollers (36,36') are deposited between the old rails (21) by means of a distributor (141). Method according to one of the preceding claims, in which the guiding of the new rail (21) takes place on the top, the sides and the bottom of the rail. Method according to one of the preceding claims, in which after the welding, the weld is deburred. Method according to Claim 4, in which the deburring takes place on the top of the slider (23) of the rail (22) and/or on the edges of the slider (23) and/or on the underside of the slider (23). Device for carrying out a method according to one of the preceding claims, comprising at least one welding train (100) consisting of transport wagons (120), new rails (20), a wagon (129) transport of a gantry (130) to move the new rails (20), a welding machine (140,150), a train for releasing and replacing the rails (200) and a recovery train ( 300) of the old rails (21). Device according to claim 6, in which the transport wagons (120) of the new rails (20) comprise a plurality of new rails (20) arranged on roller bearings (30) allowing them to move freely in the longitudinal direction. Device according to Claim 6 or 7, in which the welding machine comprises means (31-35') for longitudinally guiding the new rail (21) during its unloading from the transport wagon (120) of the new rails (20) and its laying on the ground. Device according to one of Claims 6 to 8, in which the guide means comprise rollers (31,33,34,35) and/or rollers (32). Device according to one of Claims 6 to 9, in which the welding machine comprises a distributor (141) of rolls (36, 36'). Device according to one of Claims 6 to 10, in which the train (200) for replacing and releasing the rails comprises an arm (202) for recovering the rollers (36, 36'). Device according to one of Claims 6 to 11, in which the welding machine (140, 150) comprises a chute (142) for loading the new rails (21) onto the rollers (36, 36'). Device according to one of Claims 6 to 12, in which the welding machine comprises means for deburring the shoe (23) of the new welded rails (22), the said means comprising grinding wheels (24).

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