INITIAL AND FINAL METHODS FOR LAYING LONG RAILS

Disclosed is an initial method for laying new long rails of a railway track by means of a work train travelling in a direction of travel, the initial method being intended to be implemented during a process for replacing old rails of the railway track, said method including a phase during which the new long rails are laid and subsequently fastened to sleepers of the railway track when the work train is travelling in said direction of travel, the initial laying method including a step of laying at least one portion of a first of the new long rails on the sleepers at least one end of an old joining rail.

TECHNICAL FIELD OF THE INVENTION

The invention relates, in a general manner, to the technical field of work trains such as construction and replacement trains, consisting in laying equipment necessary for the construction of railway tracks or, in the case of replacement, in replacing all or some of the materials making up the tracks, i.e. the rails and the fixed structure such as the sleepers, as well as the ballast which ensures the hold of the track on its platform, when these materials have deteriorated.

The invention relates more specifically to an initial laying method for new long rails of a railway track by a work train, a final laying method, and a method for replacing old rails, already laid, of a railway track with new long rails, which method is initiated and/or finalized by said initial and/or final laying methods for new long rails.

PRIOR ART

The builders or managers of rail transport networks need, on a regular basis, to construct new railway tracks or to re-do existing railway tracks, i.e., to replace some elements of which they are made up, such as the rails and the sleepers supporting the rails, as well as the fastening means and other accessories. A large part of this need of replacement is due to the wear of the tracks, but it can also be a case of replacing old models with more recent models in order to allow for better performance.

In the most complete case of replacement, such operations are performed using a rail convoy such as a replacing train, comprising a plurality of specialized machines for performing the different replacement operations. A typical operation of complete replacement of the railway track implements specialized rail convoys comprising machines capable of performing, in sequence, the following operations: unpacking, screening of ballast, and removal of unpacking products, by conveyor belts on cars intended for unloading, or by a direct jet to the embankment, replacement of the track to be replaced (rails and sleepers), ballasting and lifting of the track, levelling and shaping, welding of the rails, release of stresses, a new levelling/shaping, adjustment of seats, and tidying of verges.

The constant pursuit of safety and increased travel speed of rail vehicles has led to designs of rails referred to as “long welded rails” (“LWR”), or “long bars.” In the particular case of replacing rails, the replacement operation consists in replacing old rails with new long rails without interfering with the other elements of the track (platform, ballast, sleepers). It typically involves the implementation of the following steps:supplying new rails of the “LVW” types, in the form of “long bars” (for example 324 meters), previously made in welding workshops a distance from the works site, from basic rails (for example three basic rails of 108 meters each), originating from rail manufacturing factories,removal of ties and sectioning of old rails,removal of old rails, placement and alignment of new rails end-to-end, thermite welding of the new rails to one another, placed end-to-end, fastening of the new rails to the sleepers,connection of the new rails to the existing line by thermite welding, release of stresses (releasing of the ties of the new rails, striking, re-tightening of the ties), neutralizing of the rail, if necessary, using a rail driftpin, heating using gas or another method depending on the temperature at the time of substitution,loading and removal of the old rails, and cleaning of the works site.

On a track equipped with “normal” bars, the expansion is absorbed in the region of rail joints, a precisely regulated clearance between two consecutive bars allowing for a slight extension of the rails. Such a track is thus relatively insensitive to temperature variations. This is not the case for a track equipped with long bars or “LWR,” because in this case there are no joints between the rails which allow for the expansion to be absorbed. The clamping of the rail onto the sleepers, and the anchoring of the sleepers in the ballast, counter the free movement of the rails under the effect of temperature variations. Since the expansion of the rail is thwarted, it is compensated by an increase in the internal stresses of the rail. When the resistance of the ballast is no longer sufficient to counter the internal stresses of the rail, the rail thus ends up stretching, thus creating a deformation of the geometry of the chassis of the track, Such deformations of the track are obviously extremely dangerous,

In order to considerably reduce the risks of rupture of said rails due to cold weather, or deformation due to extreme heat, it is known to perform an operation of “neutralizing” the new rails. Said neutralizing makes it possible to fasten the rails at a given expansion state, either at a specified average temperature (for example 25° C.) when the neutralizing takes place by heating the rails, or with stretching of the rails corresponding to their expansion at this average temperature when the neutralizing operation is carried out by stretching of the rails.

All these operations performed step-by-step, per portion of the rails, rail after rail or long bar after long bar, require a significant amount of time as well as an interruption in travel. The same operations are required during laying of a new track, with the exception, of course, of the dismantling of the old ties and the removal of the old rails.

Solutions capable of implementing rail replacement operations comprising a step of neutralizing the rails, but at relatively low speeds, indeed which are not suitable for replacing rails for laying long welded rails, have long been known. Other existing solutions require the use of a plurality of different rail convoys for each implementing just one part of the replacement operations, which proves expensive. Furthermore, such replacement works are very long and require a larger labor force. Finally, when such solutions propose neutralizing the rail, said neutralizing proves non-existent at the ends of new rails connected to the old railway track or performed in a traditional manner using separate means.

DISCLOSURE OF THE INVENTION

The invention aims to overcome all or some of the disadvantages of the prior art by proposing in particular a solution which makes it possible to implement a method for replacing old rails by new long rails, offering the shortest possible downtime of the railway track in order to reduce the duration of the work, while ensuring good safety of the laid railway track, in particular at the ends of the old rails surrounding a portion of the rail to be replaced, corresponding to the ends of new rails connected to the old railway track.

In order to achieve this, according to a first aspect of the invention an initial method for laying new long rails of a railway track by means of a work train travelling in a direction of travel is proposed, the initial method being intended to be implemented during a process for replacing old rails of the railway track of the type comprising a phase during which the new long rails are laid and subsequently fastened to a fixed structure of the railway track when the work train is travelling in said direction of travel, the initial laying method comprising:a step of laying at least one portion of a first of the new long rails on the fixed structure at at least one end of an old joining rail;a temporary end-to-end connection step for connecting the end of the old joining rail to at least one end of the first new long rail by means of at least one temporary connection device;a step of permanent connection, for example by welding, for example therrnite welding, of the two connected ends of the old joining rail and the first new long rail;the initial laying method being characterized in that it comprises, prior to the laying step, a step of heating or cooling, for neutralizing to the reference temperature, at least one end portion of the first new long rail, the end portion comprising the end of the first new long rail to which the end of the old joining rail is required to be connected.

“Long rails” means rails also referred to as “long welded rails” (“LWR”) or “long bars.” These long welded rails are formed from one or from a plurality of basic rails of normal length, or “normal bars,” welded together, generally in welding workshops a distance from the works site, and thus forming a single continuous unit. The distinction between long welded rails and rails consisting of normal bars is thus very clear in terms of length, it being possible for the long welded rails to extend over several hundred meters, or indeed kilometers. In this case, the railway track refers both to tracks laid on ballast, or tracks without ballast laid on other supports (tracks laid on concrete, tracks laid on slabs, etc.). The fixed structure of the railway track may vary in function and comprise for example, depending on the type of railway track, sleepers, slabs, a concrete platform, etc.

By virtue of such a combination of features, a method of this kind allows for a connection between the old railway track and the new railway track, with a level of safety that is guaranteed by neutralizing the rails, prior to fastening them, in a manner equivalent to the remainder of the track, in particular in this case in the region of the end portion of the first new long rail. Of course, the initial laying method may be implemented on a line of rails of the railway track, or indeed concurrently on the two parallel lines of rails of the railway track.

According to one embodiment, the initial laying method comprises a step of neutralizing, preferably by heating or cooling, an end portion of the old joining rail comprising the end of the old joining rail to which the end portion of the first new long rail is required to be connected.

According to one embodiment, the step of heating or cooling for neutralizing, to the reference temperature, the end portion of the first new long rail is preceded by the step of neutralizing, preferably by heating or cooling, the end portion of the old joining rail comprising the end of the old joining rail to which the end portion of the first new long rail is required to be connected.

According to one embodiment, the step of heating or cooling for neutralizing the end portion of the old joining rail is performed by heat transfer or insulation means which preferably comprise an infrared radiation source for heating said end portion of the old joining rail to the reference temperature.

According to one embodiment, prior to the step of end-to-end connection of the end of the old joining rail to the end of the first new long rail by the temporary connection device, a step of cutting the old joining rail is performed, in order to form the end of the old joining rail which is to be connected.

According to one embodiment, the temporary connection device comprises at least one fishplate or rail driftpin. The temporary connection devices such as the fishplate or the rail driftpin have the function of keeping the ends of the rails abutted, whatever the outside temperature variations, in order to thus guarantee the perfect joining of the ends. Another function is to retain the reference length of the old and of the new rail, until the step of welding the ends. Said temporary connection device is removed once the ends of the rails are welded, and once the weld has cooled after a predetermined cooling time, generally twenty minutes. The permanent connection, subsequent to the temporary connection, makes it possible to ensure travel at a normal speed, of a rail vehicle, while the temporary connection allows, at best, for travel at a reduced speed.

According to one embodiment, prior to or following the step of temporary end-to-end connection of the end of the old joining rail to the end of the first new long rail by the temporary connection device, said ends undergoing a preparation step in view of the permanent connection step, for example a step of abrasive machining.

According to another aspect of the invention, this relates to a final method for laying new long rails of a railway track by means of a work train travelling in a direction of travel, the final method being intended to be implemented during a process for replacing old rails of the railway track of the type comprising a phase during which the new long rails are laid and subsequently fastened to a fixed structure of the railway track when the work train is travelling in said direction of travel, the final laying method comprising:a step of laying at least one portion of a last of the new long rails on the fixed structure at at least one end of an old joining rail;a temporary end-to-end connection step for connecting an end of the last new long rail to at least the end of the old joining rail by means of at least one temporary connection device;a step of permanent connection, for example by welding, for example therrnite welding, of the two connected ends of the old joining rail and the last new long rail;the final laying method being characterized in that it comprises, prior to the laying step, a step of heating or cooling, for neutralizing, to the reference temperature, at least one end portion of the last new long rail, the end portion comprising the end of the last new long rail to which the end of the old joining rail is required to be connected.

According to one embodiment, the final laying method comprises a step of neutralizing, preferably by heating or cooling, an end portion of the old joining rail comprising the end of the old joining rail to which the end portion of the first new long rail is required to be connected.

According to one embodiment, the step of heating or cooling for neutralizing, to the reference temperature, the end portion of the last new long rail is followed by the step of neutralizing, preferably by heating or cooling, the end portion of the old joining rail comprising the end of the old joining rail to which the end portion of the last new long rail is required to be connected.

The steps implemented, and the means used for this final method are similar, mutatis mutandis, to the initial method. Thus, and in the same way as for the end portion of the first new long rail, a method of this kind allows for a connection between the old railway track and the new railway track, with a level of safety that is guaranteed by neutralizing the rails, prior to fastening them, in a manner comparable to the remainder of the track, in particular in this case in the region of the end portion of the last new long rail.

According to another aspect, the invention also relates to a method for replacing old rails of a railway track of the type comprising a phase during which the new long rails are laid and subsequently fastened to a fixed structure of the railway track by a work train travelling in a direction of travel, the replacement method being characterized in that the phase is initiated by the initial method for laying new long rails as described above, and/or finalized by the final method for laying new long rails as described above.

According to one embodiment, the replacement method comprises a first phase during which new long rails are unloaded along the railway track from a transport train of a work train travelling in a first direction of travel, and comprises a second phase in which the work train travels in a second direction of travel opposite the first direction of travel, the new long rails being laid and subsequently fastened on the fixed structure, such as the sleepers of the railway track, during the second phase.

A replacement method of this kind can be implemented by one single work train. Furthermore, the operations performed can be sequenced in an optimized manner. It is no longer necessary to perform all the operations at the same time, or in a manner sequenced successively according to a single direction of travel, which would have the effect of reducing the speed of travel on the works site, depending on the most restrictive operation. Indeed, when the work train implements all the operations in series, just one operation requiring the immobilization of the work train is sufficient to limit the progression of the work regarding the other operations. Proceeding in a sequenced manner of this kind, in two phases, and distributing the replacement operations in one direction of travel and then in the other direction of travel, a reduction in the works time for an equivalent length of replaced rails has been identified. Finally, it is possible to perform all these operations during the same temporary interruption of travel, while minimizing the duration of this interruption.

According to one embodiment, the work train comprises vehicles mounted on wheel sets, for example bogies, the step of neutralizing by heating or cooling for neutralizing being performed in a zone of the work train located upstream of the first of the wheel sets of the work train, with respect to the new long rails, in relation to the second direction of travel.

According to one embodiment, the heating or cooling neutralizing step is followed by a step of holding and/or correction of the reference temperature of the neutralized portion of rail, by heat transfer or insulation, the step of holding and/or correction of the reference temperature preferably being carried out in a zone of the work train located at least downstream of the first of the wheel sets with respect to the new long rails, in relation to the second direction of travel. Preferably, the heat transfer or insulation means comprise an infrared radiation source. During a step of holding and/or correction of the reference state, the holding means can ensure a correction of the neutralization, in addition to said neutralizing step, so as, for example, to aim towards a reference state which would not have been achieved during the previous neutralizing step.

Once the new long rails are laid on the fixed structure, a certain distance separates the laying zone of said rails from a fastening zone of said rails to the fixed structure. Such a step of holding and/or correction of the reference state, for example the reference temperature, downstream in reference to the second direction of travel and at a distance from the neutralizing step, makes it possible to ensure fixing of the neutralized new long rails, in particular at a temperature that is held at the reference temperature. This makes it possible to further reduce the risks of said rails breaking or of the track deforming according to the heat differences to which they are exposed.

The initial method is an initial or engagement phase of the steps of laying the new long rails and dismantling the old rails by the work train, in order to start the replacement, proceeding from this initial configuration, of a portion of the railway track.

Preferably, the neutralizing during the initial laying method for the end portion of the old joining rail is performed by all or some of the means for holding and/or correcting the reference temperature.

The final method is a final or disengagement phase of the steps of laying the new long rails and dismantling the old rails by the work train, in order to finalize the replacement of a portion of the railway track.

Preferably, the neutralizing during the final laying method for the end portion of the old joining rail is performed by all or some of the means for holding and/or correcting the reference state.

For reasons of improved clarity, the identical or similar elements are indicated by identical reference signs in all the figures.

DETAILED DESCRIPTION OF AN EMBODIMENT

FIGS.1,2A,2B,2C and2Dare schematic views of a rail convoy10comprising a work train100according to an embodiment of the invention. The work train100comprises an engine110at the front of the train, followed, in this case directly, by a transport train120coupled to the engine110. The transport train120is designed to ensure the transport of new long rails22to be transported on a works zone ZO, and preferably also to store old rails21to be removed from this same works zone ZO, as the new long rails22are laid. The work train100comprises a works train130coupled to the rear of the transport train120. The works train130is illustrated in a variant equipped with three works vehicles131,132,133coupled successively, in particular a first works vehicle131, a second works vehicle132, and a third works vehicle133. It is of a variable composition, i.e. its composition of cars may vary at points, for example when passing into a workshop, but which, once specified, generally for a specific works site, does not change any more apart from when passing into a workshop.

It will be noted that the “old” rails extend in the manner of rails already laid, pre-existing on a track to be replaced, the new rails extending in the manner of rails coming to replace said rails already laid. These terms do not indicate the wear or aging of the rail per se.

The rail convoy10comprises a welding machine140, which is in this case a railway machine which can be detachably coupled at the end of the work train100, in particular here at the end of the works train130, in relation to a first direction of travel F1. Such coupling makes it possible to move a rail convoy as far as the works zone Z0. The welding machine140is intended to be uncoupled from the work train100once it has arrived in the vicinity of the works zone Z0, as shown inFIG.1, so as to be able to travel independently of the work train100, preferably at a distance from the work train100, Its use will be better understood upon reading the replacement method described below.

FIGS.3A and3Bare schematic views of said rail convoy10, in a first and a second phase A, B, respectively, of the replacement of the railway track20—this is the replacement of the old rails21of the railway track20with new long rails22. The method for replacing old rails21of the railway track20with new long rails22is made up, overall, of:a first phase A during which new long rails22are unloaded along the railway track20from the transport train120of the work train100travelling in a first direction of travel F1, anda second phase B during which the work train travels on a reverse path, i.e. in a second direction of travel F2opposite the first direction of travel F1, and during which the new long rails22are laid and subsequently fastened on a fixed structure23, of the railway track20, in this case sleepers23.

In other words, the work train100moves on the railway track20in two phases, out A and back B, during which it implements different steps, the combination of these two phases A and B making it possible to ensure the replacement of the railway track20.

During the first phase A, the new long rails22are unloaded successively along the railway track20, from the transport train120of the work train100, while the work train advances according to the first direction of travel F1drawn by the engine110. The engine110may selectively provide, or not, a traction aid for the work train100, which is equipped with its own advancement system, in particular by distributed driving wheel sets. Thus, the delivery onto the works site can be carried out according to two variants: using a self-propelled machine specific to the work train, or by being towed by a locomotive. On the works site, the self-propelled machine can also be assisted by a traction ensured by the locomotive.

Depending on the desired configuration, these new long rails22can be unloaded outside of the railway track20, along old rails21to be replaced, or in the center of the railway track20. Once the first phase A is ended, this results in an alignment of new long rails to be laid, arranged successively along the railway track20and in the vicinity thereof. A step of placement on the ground of supports, such as roller supports, is implemented prior to the unloading of the new long rails, preferably by one of the vehicles of the works train130, such that the new long rails come to rest, on the ground, on these roller supports, and not directly on the ground or the ballast. The station107′ designed to ensure the laying or placement of roller supports is located upstream of that of the unloading of the new long rails22, with reference to said first direction of travel F1. In this example, the work station107′ ensuring the placement of the roller supports is implemented by the first vehicle131of the works train, in front of the second vehicle132in the region of which the unloading is ensured, with reference to said first direction of travel F1.

In parallel with this operation of unloading of the new long rails22along the railway track20, still during the first phase A, each of the ends of the new long rails22unloaded undergoes a step of preparation with a view to a step of permanent connection, for example welding. Such a preparation step comprises, for example, a step of abrasive machining. Said step of preparation for the welding is implemented by a welding preparation post116borne by the welding machine140. In this example, said welding machine140is a railway machine. In particular configurations, the welding machine could also be a welding rail-road truck or a welding rail-road excavator. The welding machine140travels independently of the work train100and in the first direction of travel F1, behind it. During the first phase A, the welding machine140thus travels generally in the same direction F1as the work train100, at a distance d behind it, said distance being variable during the first phase A. In this way, while the work train100progresses at a virtually continuous and homogeneous speed for unloading the new long rails22, with some short breaks, so as to guide the new long rails22towards a laying zone of the train, said breaks marking stages A3in the progression of the work (seeFIG.7), the welding machine140progresses at a different speed and in a sequenced manner, alternating static phases, during the preparation for the welding of the ends of the new long rails22, and dynamic phases where it progresses along the railway track20in order to reach a following end, and so on.

During the second phase B, the work train moves according to a second direction of travel F2opposite the first direction of travel F1, thus travelling the reverse path. The rail convoy10comprises, successively, from the front to the rear with respect to the first direction of travel F1, the locomotive110(which is optional if it is not used as a traction aid during the work), then the transport train120and the works train130then travel in a reverse order—the works train130is positioned at the front of the work train100, with reference to this second direction of travel F2. The welding machine140which traveled independently and at a distance behind the work train during the first phase A still travels independently and at a distance from the work train100during the second phase B, but this time in front of it, with reference to said second direction of travel F2.

A plurality of operations are implemented substantially concurrently during said second phase B.

The old rails21of the portion of railway track to be replaced are dismantled by the work train100, then preferably loaded onto the transport train120of the work train100. The old rails21are coupled at regular intervals while they are loaded on the transport train120of the work train100in order to be stored in a plurality of separate sections of old rails21. In this way, the transport train120can be used to store both the new long rails22and the old rails21. Another possible alternative is that the old rails21are moved along the railway track20from the railway track20itself, in particular from their location on the sleepers23, The transport train120is provided with handling equipment121such as handling frame which makes it possible to ensure a certain number of operations, such as the cutting of the old rails21, or the gripping of the rails21,22, etc. Alternatively, or in addition, these operations can also be carried out entirely or partially manually. The loading path of the old rails21preferably follows the reverse path of that of the unloading of the new rails22, In this way, the multiplication of equipment, in particular on the second vehicle132of the works train130, is limited.

The welding machine140, which thus travels, during said second phase, in front of the work train100and in the same direction of travel F2as the work train, comprises welding means115and in turn carries out welding operations, preferably electric welding, of the new long rails22, end-to-end. The welding machine140operates at a sufficient distance from the work train100so as to allow for the cooling of the electric weld before the laying of the new long rail22. A cooling time on the order of for example20minutes can thus be ensured,

The laying of the new long rails22on the sleepers23of the railway track20is ensured by the work train100in the region of a laying zone Z1located downstream of the welding machine140, This laying operation consists in particular, but not exclusively, of moving the new long rails22arranged along the railway track20, in order to install them on the sleepers23, in the same place where the old rails21are previously dismantled, said dismantling taking place in a dismantling zone Z6which is upstream with respect to the laying zone Z1The dismantling of the old rails21and the laying of the new long rails22are carried out in parallel, and thus progress in a synchronized manner. The same vehicle132of the works train130mainly implements the dismantling and laying steps, such that the laying Z1and dismantling zones Z6are located perpendicularly to the same vehicle132of the works train130, said steps being implemented by the same second vehicle132. In this way, the discontinuity of the railway track20brought about by the dismantling of the old rails21and the laying of the new long rails22is spanned by the same vehicle132borne by a wheel set such as an upstream bogie101with respect to the second direction of travel F2, moving on the old rails21, and a wheel set such as a downstream bogie101moving on the new long rails22positioned on the sleepers23. Said downstream bogie101of the vehicle132implementing these two steps constitutes the first of the bogies101of the work train100with respect to the new long rails22, in relation to the second direction of travel F2.

A step of neutralizing, by portions24, the new long rails22by heating or cooling to a reference temperature is implemented in order to allow fastening of the rails at a given dilation reference state. During said neutralizing step, located in a zone Z2(seeFIG.4), each of the portions24of the new long rails22is heated or cooled to the reference temperature by main neutralizing means111located in the same zone Z2before being laid on the sleepers23of the railway track20. The main neutralizing means111preferably comprise a heating means, such as an induction heating means. Preferably, the main neutralizing means111comprise cooling means, for example equipment for projecting a flow of liquid such as water or a gas flow, ideally air, optionally compressed, dry ice, etc.

Said neutralizing zone Z2is located upstream of the first of the wheel sets, in particular in this case bogies,101of the work train100with respect to the new long rails22, in relation to the second direction of travel F2.

In order to avoid too significant a temperature difference between the reference temperature and the temperature of the rails at the time of their fastening to the sleepers23, the heating or cooling neutralizing step is followed by a step of holding and/or correction of the reference temperature of the neutralized portion of rail24, by heat transfer or insulation. Preferably, the heat transfer or insulation means comprise an infrared radiation source.

Said step of holding and/or correction of the reference temperature is carried out in a zone Z3of the work train100located at least downstream of the neutralizing zone Z2and downstream of the first of the bogies101with respect to the new long rails22, in relation to the second direction of travel F2. In a variant shown inFIG.4, said zone Z3continues downstream of the second bogie with respect to the new rails. The new long rails22are then fastened to the sleepers23by ties in a zone Z4of the work train100located directly downstream of the zone Z3of the work train in which the step of holding and/or correction of the reference temperature is carried out. Said step of holding and/or correction of the reference state, i.e., the reference temperature, is implemented by at least holding and/or correction means113of the reference temperature, located in the region of said same zone Z3.

Of course, an additional step of holding and/or correction of the reference temperature of the neutralized rail portion24by heat transfer or insulation can be implemented on another holding and/or correction zone Z5of the upstream reference temperature, for example by additional holding and/or correction means112of the reference temperature, upstream of the first bogies101with respect to the new long rails22, and downstream of the neutralizing zone Z2(seeFIG.4). Indeed, a notable distance separates the main neutralizing means111of the first of the bogies101with respect to the new long rails22, approximately8m in this embodiment, which justifies the interest in such an additional device for holding and/or correction112of the upstream reference temperature. Of course other additional holding means for the reference temperature can be used, such as additional holding and/or correction means114of the reference temperature which are located between the means113and112, in the region of the first and second bogies101with respect to the new long rails22the first of the bogies101with respect to the new long rails22forming the downstream bogie of the second vehicle132, and the second of the bogies101with respect to the new long rails22forming the upstream bogie of the first vehicle131which precedes it with reference to the second direction of travel F2.

Ideally, the step of holding and/or correction of the reference step is implemented over the entire portion of rail located between its neutralizing and its fastening, the fastening of ties being directly downstream of the holding and/or correction to the reference state. In practice, on account of the presence of some equipment or a work station necessary for example for the laying of the ties107before their fastening (screws and/or clips) by a work station108, it will be ensured that the distance separating a zone Z4of the work train in which the step of fastening of the new long rail is performed from the zone Z3of the work train in which the step of holding and/or correction of the reference state is performed, i.e. less than7m.

During said second phase B, initial and final phases must be implemented in order to initiate and finalize the laying of the new long rails22, at the same time as the dismantling of the old rails21with respect to the pre-existing railway track to which its connection must be ensured.

In order to achieve this, the second phase B comprises an initial phase, illustrated in detail inFIGS.5A,5B,5C,5D,5E and5F. In these figures, only the first and second vehicles131and132of the works train130are illustrated, in order to simplify the views. In an initial configuration, the old rails21extend continuously and are fastened to the sleepers23by ties (not shown), while the new long rails22are laid along the railway track (seeFIG.5A). The initial phase corresponds to the engagement of the steps of laying the new long rails22and dismantling the old rails21by the work train100, in order to start the replacement, proceeding from this initial configuration. Said initial phase comprises in particular, but not exclusively, the following steps, preferably for each of the two parallel rails in the same region of the railway track20:a step of dismantling the ties fastening the old rails in the vicinity of and downstream of the rails to be replaced, i.e. on a portion located downstream of an end211′ of an old joining rail211to which an end portion221′ of a first of the new long rails221, with respect to the second direction of travel F2(seeFIG.5B), has to be connected: said step of dismantling the ties is implemented by dismantling means102preferably located in the region of the third upstream vehicle133of the works train130in said direction of travel F2when it is used or can be implemented also upstream of the vehicle132implementing the neutralizing step;a step of heating or cooling for neutralizing the end portion211′ of the old joining rail211downstream of the end211′ thereof to which the end portion221′ of the first new long rails221, with respect to the second direction of travel F2(seeFIG.5B), has to be connected, the end portion211′ comprising the end211′ of the old joining rail211to which the end portion221′ of the first new long rail has to be connected: said heating or cooling step is preferably implemented by the holding and/or correction means113,114,112for the reference temperature, rather than by the neutralizing heating or cooling means111. Said heat transfer or insulation means are borne in part (112) by the second vehicle132coupled in front of the first vehicle131and located downstream of the works train130in said direction of travel F2;a step of cutting the old rail21, in particular the old joining rail211(seeFIG.5C), thus creating a discontinuity of the railway track20in a position when the discontinuity of the railway track20is spanned by the vehicle132performing the neutralizing heating or cooling, the dismantling of the old rails21and the laying of the new long rails22as the train travels according to the direction of travel F2;a step of heating or cooling for neutralizing the end portion221′ of the first new long rail221comprising the end221′ to which the end211′ of the old joining rail211has to be connected;after laying of at least a portion of at least the first new long rail221on the sleepers23at the end211′ of the old joining rail211, a step of temporary end-to-end connection of the end211′ of the old joining rail211to the end221′ of the first new long rail221by a temporary connection device30such as a fishplate or a rail driftpin (seeFIG.5D), ensuring the passage of the bogies101and making it possible to retain an end-to-end and ideally neutral position, despite possible outside temperature variations;when the work train100has passed the temporary connection device30, a step of permanent connection, for example welding, preferably thermite welding, of the two connected ends211′,221′, followed by a step of removal of the temporary connection device30.

In a particular configuration, the heating or the cooling of the end portion211′ of the old joining rail211upstream of the end211′ thereof before the cutting of the rail can be ensured by the at least one neutralizing heating or cooling means111, and/or by all or some of the holding and/or correction means112,113,114of the reference temperature. In this latter case, the neutralizing heating or cooling means111can preferably be activated only from the step of neutralizing the end portion221′ of the first of the new long rails221to the reference temperature. The advantage of using only all or some of the holding and/or correction means112,113,114of the reference temperature is that at this location the old joining rails211are laid on the sleepers23, and the use of neutralizing means111such as induction heating could damage the ties of the old rails which, like the rails, are also metal. The heating for holding and/or correction112,113,114is less powerful than the induction heating111and prevents damage to the ties. This is easier to implement than using a power variation means for the neutralizing means111, in particular induction heating means, which would make the equipment more expensive and more complex. The heating or cooling of the end portion211′ of the old joining rail211is preferably carried out over a distance greater than the zone on which the ties are dismantled (seeFIG.5B).

The second phase B also comprises a final phase corresponding to the disengagement of the steps of laying the new long rails22and dismantling the old rails21by the work train100, in order to finalize the replacement. Said final phase is illustrated in detail inFIGS.6A,6B,6C,6D,6E and6F, and comprises in particular, but not exclusively, the following steps, preferably for each of the two parallel rails in the same region of the railway track20:a step of heating or cooling for neutralizing, to the reference temperature, an end portion222′ of a last of the new long rails222, the end portion comprising the end222′ of the last new long rail222to which the old railway track20has to be connected (seeFIG.6B);a step of cutting the old rail21, defining an end212′ of an old joining rail212(seeFIG.60);a step of temporary end-to-end connection of the end222′ of the last new long rail222to the end212′ of the corresponding old joining rail212by at least one temporary connection device30such as a fishplate or a rail driftpin (seeFIG.6D) which allows the rails to either stretch freely but not to retract in the case of use of heating, or to retract freely but not to stretch in the case of use of cooling, and thus to maintain a neutral position despite possible outside temperature variations;a step of heating or cooling for neutralizing an end portion212′ of the old joining rail212located upstream of its end212′ to which the end portion222′ of the last new long rail222, with respect to the second direction of travel F2, has to be connected (seeFIG.6D), the end portion212′ of the old joining rail212comprising the end212′ of the old joining rail to which the end portion of the last new long rail222has to be connected: said step of heating or cooling is preferably implemented by the holding and/or correction means113,114,112of the reference temperature, rather than by the neutralizing heating or cooling means111, the heating or cooling of the end portion212′ of the old joining rail212preferably being carried out over a distance greater than the zone on which the ties are dismantled (seeFIG.6E);when the work train100has passed the temporary connection device30, a step of permanent connection, for example welding, for example thermite welding, of the two connected ends212′,222′ followed by a step of removal of the temporary connection device30.

During the entire progression of the work train130, according to the second direction of travel F2:a work station102arranged on a front part of the works train130, in this case upstream of the third vehicle133in the direction of travel F2, is designed to remove the ties of the rails which fastens them to the sleepers23such that a detached portion P1of the railway track20is no longer fastened by the ties;a work station103, borne by the third vehicle133and arranged downstream of the work station102for removing the ties, is designed to collect the removed ties;a work station104, borne by the second vehicle132and arranged downstream of the work station103for collecting ties, is designed to dismantle old tie pads, generally made of rubber, which are located between the sleeper and the bottom of the rail, said tie pads having the role of damping some of the vibrations and allowing the longitudinal progress of the rail without damaging the sleeper23;a work station105, borne by the second vehicle132and arranged downstream of the work station104for dismantling old tie pads and upstream of the neutralizing means111, is designed for depositing new tie pads on the sleepers23on which the new long rails22will come to rest;a work station106, borne by the first vehicle131and arranged downstream of holding and/or correction means113for the reference temperature located in the region of the zone Z3, is designed for collecting the old tie pads dismantled by the work station104;a work station107, borne by the first vehicle131and arranged downstream of the work station106for collecting old tie pads, designed for placing the ties; anda work station108, bone by the first vehicle131and arranged downstream of the work station107for placing the ties, designed for fastening the rail ties and thus fastening said rails to the sleepers23, such that an attached portion P2of the railway track20is blocked by the ties.

In this way, a new rail is neutralized in a detached state, Of course, these work stations can be substantially shifted. As described, in a configuration comprising a third car133, it is this car133which can ensure the removal of the rail ties. A step of collecting the ties is then preferably implemented directly after their removal, The new long rails22are, in turn, attached either using new ties or using old ties previously removed and then collected, in order to ensure recycling of the ties if their state allows this.

It will be noted that “work station” means any work station making it possible to receive people for performing manual operations, and/or any equipment intended for performing these operations in an automatic or semi-automatic manner.

Furthermore, during said second phase B, the removal of the ties, and thus the subsequent blocking of the ties, is implemented proceeding from a downstream portion at the end211′ of the old joining rail211comprising the end211′ to which the end221′ of the first new long rail221has to be connected, and extends as far as an upstream portion at the end212′ of the old joining rail212comprising the end212′ to which the end222′ of the last new long rail222, with reference to the second direction of travel F2, has to be connected. In this way, the laying of new long rails is carried out at a reference temperature, said laying being followed by operations aiming to subsequently fasten it in accordance with the predetermined reference temperature.

FIG.7is a graph illustrating the operation of the rail convoy10, in particular its progression along the railway track20, the x axis showing the time progression during the work, and the y axis showing the position with respect to the railway track20. A first curve C100, here the top curve, corresponds to the progression of the work train100, and a second curve C140, below the curve C100, corresponds to the progression of the rail vehicle140travelling independently and at a distance d from the work train100.

During the first phase A, the work train100moves from a starting position X0as far as an end position X1, along the railway track20, During this movement according to the first direction of travel F1, the work train100alternates dynamic steps A1, of unloading new long rails22along the railway track20, and static steps A3, marking stages during which each new long rail is engaged in guide tunnels for the work train in order to ensure the correct unloading of these new long rails22along the railway track20.

In parallel with the progression of the work train100, the rail vehicle140progresses in stages, alternating static steps A2of preparation for welding, and dynamic steps A4of movement from one abutting end of two new long rails to another abutting end, according to the first direction of travel F1.

Following the first phase A the second phase B continues, during which the work train100moves from the end position X1as far as the starting position X0, along the railway track20. During this movement according to the second direction of travel F2, the work train100alternates between dynamic steps B3of loading old rails21onto the transport train120, and static steps B5marking stages during which the old rail21is cut during its loading, such that it can be stored in a plurality of basic sections, on the transport train120.

In an embodiment of this kind, tests have shown that the work train100could progress at a speed of 2500 m/h during the first phase A, and at a speed of 600 m/h during the second phase B, while being able to progress according to working radii of 250 m and on gradients of 40%. Such a method according to the invention also offers the advantage of being able to be implemented, if required, while leaving free possible adjacent railway tracks which can thus be travelled on entirely safely.

In parallel with the progression of the work train100during said second phase B, the rail vehicle140progresses in stages, alternating steps B2of welding and steps B4of movement from one abutting end of two new long rails to another, according to the second direction of travel F2. The steps B6and B7mark a movement of the welding machine140and of the work train100, respectively, in the continuation of its progression and beyond the starting position X0, in order to ensure the welding between the two connected ends212′,222′ at the end of the work. The initial phases B1(FIGS.5A to5F) and final phases B4(FIGS.6A to6F) of the second phase B are indicated by stages, which is a simplification given the very low speed of movement of the work train100during these two phases A and B. Furthermore, such a method makes it possible to easily and relatively rapidly implement the electric welding operations of the LWR rails, the dismantling and the re-mounting of the rail ties, and the neutralizing of the rails.

Of course, the invention is described above by way of example. It will be understood that a person skilled in the art is able to implement different variants of the invention without in any way departing from the scope of the invention.

For example, the composition of the work train may be different. The works train may comprise just two cars, as shown inFIGS.5and6, or three cars as shown inFIGS.1,2,3and4. More precisely, it is possible to design the work train so as to work without the third work vehicle133of the work train130. In such a design, the ties of the old track could be dismantled using manual tools, upstream of the rail convoy, with reference to the second direction of travel F2.

Furthermore, the rails can be replaced in parallel, two-by-two, so as to replace all the railway track during the operations, and/or successively along one side only of the railway track, so as to replace the rails of a single line. Indeed, it can be envisaged that only successive rails of one single side of the railway track will be replaced, which may be of interest on sections of railway track such as curved sections. In other words, the initial and/or final laying methods may be implemented, as for the replacement, on a line of rails of the railway track, or indeed concurrently on the two parallel lines of rails of the railway track.

In an alternative or additional design, the neutralizing can be achieved other than by heating or cooling, by mechanical stresses likely to cause portions of rails to be stretched in a manner corresponding to their expansion at said reference temperature. The reference state thus corresponds to an expansion state given by way of reference, which itself corresponds to a state of the rail portion if it were exposed to said reference temperature.

It can also be envisaged that the first and second phases A and B are implemented in a temporally spaced manner, it being possible for the first phase A to be implemented one night, and the second phase B to be implemented a following night.

Regarding the dismantling of the old rails, in place of being loaded onto the transport train the old rails could also be unloaded along the railway track from their position laid on the sleepers.

The bogies can also be formed by any type of wheel set.

Such a rail convoy is of particular interest in that it allows for replacement of a railway track which offers the shortest possible immobilization of the railway track in order to reduce the duration of the work, while ensuring good safety of the laid railway track. Of course, it is also possible to use a rail convoy of this kind for operations which do not involve all the steps. The rail convoy can be used to simply transport and unload the new long rails along the railway track from the transport train, either outside of the railway track or inside, with an optional operation of welding and placement of roller supports.

It is emphasized that all the features, as they follow for a person skilled in the art from the present description, the drawings, and the accompanying claims, even if they have been specifically described only in relation with other specific features, both individually and in any combination, can be combined with other features or groups of features disclosed herein, provided that this is not explicitly excluded or that technical circumstances render such combinations impossible or meaningless.