Patent Application
20240158993
The invention relates to a method for cleaning a ballast bed of a track by means of track-bound machines, with ballast located below a track panel being removed by means of a cleaning machine using a ballast removal device, with cleaned and/or new ballast being placed behind, in relation to a working direction, in the track in several layers by means of a ballast placement device and a ballast train, and with the placed ballast being compacted by means of a tamping machine and a stabilizing machine.
Ballasted tracks have properties that enable safe and efficient railway operations. The main requirement of a ballasted track is to absorb static and dynamic loads. For this purpose, the ballast must have sufficient stability and elasticity due to a suitable grain distribution and good interlocking of the individual ballast grains. A low percentage of fine particles and high sharpness of the edges are decisive for this requirement.
Over longer periods of time, dynamic operational loads and weather influences cause the ballast to increasingly lose its positive properties. To restore an intact ballast bed, ballast must be cleaned, added, or completely replaced. A machine for carrying out ballast cleaning is known, for example, from AT 520989 A1. By means of a ballast removal device designed as an endless excavating chain, the ballast located below the lifted track panel is continuously removed and fed to a cleaning system. Immediately behind this, cleaned and/or new ballast is placed on the existing formation by means of a ballast placement device.
The publication Schilling R.: Schotterbettreinigung auf eingleisigen Eisenbahnstrecken [Ballast bed cleaning on single-track railway lines]. ZEVrail Glasers Annalen 129, Hanover, 10 Oct. 2005, pp. 414-422, describes the process of ballast cleaning with all the preparatory and main work. To compact the ballast placed after cleaning, several machines of a so-called mechanized maintenance train are used. Such a train includes a tamping machine, a ballast plough, and a Dynamic Track Stabilizer.
According to prior art, a first ballast compaction pass takes place immediately after the cleaning machine. Afterwards, new ballast is discharged over the track panel by means of a ballast train consisting of ballast self-unloading trailers. The track panel is lifted and the new ballast is compacted below the sleepers by means of the mechanized maintenance train. This process of supplying new ballast, track lifting, and compaction repeats itself to achieve a ballast bed with the desired height.
This common practice is explained in detail with reference to
The top illustration shows the first work phase of ballast excavation and ballasting during a lifting of the track panel. The ballast is removed from below the lifted track panel with an excavating chain. The excavating height is usually 300 mm. The removed old ballast is screened and sharpened. This cleaned ballast part is returned to the track by means of a ballast conveyor belt and distributed to a maximum initial height of 150 mm by means of a plough. This maximum initial height is specified by regulations of various railway infrastructure managers, for example, the French SNCF. In accordance with the regulations, the ballast is compacted immediately afterwards using a stabilizing unit, with the ballast bed height being lowered to approx. 130 mm.
In a second work phase, new ballast is placed by means of a ballast train and distributed by means of a plough. The track panel is then lifted by 80 mm, while the lifted sleepers are tamped simultaneously. A subsequent stabilizing process leads to a settlement of the track panel. The remaining height of the ballast bed below the sleepers is approx. 205 mm.
The third work phase is a repetition of the second work phase, with a further lift of 80 mm and a settlement to approx. 280 mm taking place. The ballast in the track is usually sufficient to carry out a final tamping process in a fourth work phase. However, it may also be necessary to discharge new ballast in front of the tamping machine.
In the final pass, the tamping machine brings the track panel into a predefined geometry with a lift of 20 mm to 25 mm. The subsequent stabilization causes a lowering to the original ballast bed height of approx. 300 mm. In a final work step, profiling of the ballast bed and sweeping to remove ballast grains lying on the sleepers takes place.
The multi-layered placement of the ballast described requires long track possessions. If necessary, the work must be divided among several track possessions; in the meantime, the track can only be re-opened to railway traffic at a significantly reduced speed.
The object of the invention is to improve a method of the kind mentioned above in such a way that all work can be carried out in a shortened track possession compared to prior art. The quality of the compacted ballast bed should meet the specifications of the railway infrastructure managers.
According to the invention, this object is achieved by the features of independent claim 1. Dependent claims indicate advantageous embodiments of the invention.
Here, prior to a first tamping process, all layers of the new and/or cleaned ballast are placed by means of the ballast placement device and the ballast train, with the ballast bed being compacted in different depth layers during the first tamping process by means of a deep tamping unit arranged on the tamping machine, with the track then being stabilized by means of the stabilizing machine, with the track panel then being immediately tamped in only one depth layer by means of the same or a further tamping machine in a second tamping process, and with the track being stabilized after the second tamping process by means of the same or a further stabilizing machine. Compared to the known method, this eliminates the need for a separate ballast placement by means of a further ballast train as well as a subsequent tamping process and a stabilizing process.
In addition to shortening the necessary track possession, the new method has the advantage that more cleaned ballast can be reused compared to the known method. This ballast is placed in the track immediately after cleaning via the ballast placement device and must not be temporarily stored or replaced by new ballast.
With the new method, only one ballast train is needed for the cleaning worksite. If necessary, material conveyor and hopper units (MFS) coupled to the cleaning machine can be used to bring additional new ballast to the worksite. In the conventional method, the material conveyor and hopper units are hauled empty to the worksite and loaded with spoil.
Another advantage is the reduction in tamping processes, which protects the ballast. Additionally, a work pass is also eliminated for the ballast plough and the track stabilizer. This reduction of work processes means that fewer personnel is needed on the track. This reduces labour costs and contributes to the safety of the track worksite.
Overall, the length of the worksite is reduced due to the elimination of the machines and ballast self-unloading trailers previously required. As a result, the effort required to secure the worksite is also reduced. Less safety personnel and less safety equipment are needed. Additionally, on an adjacent track, the line with restricted travelling speed is shortened, which allows more trains to travel past the worksite.
Advantageously, in the method according to the invention, the ballast bed is cleaned at least with a removal height of 300 mm. This does not result in any losses compared to the conventional method, with the required compaction quality being achieved with the deep tamping process.
A further improvement provides that ballast for a bed height of at least 200 mm, particularly of at least 250 mm, is placed by means of the ballast placement device. This ensures that the original ballast bed height is reached with the remaining lifting processes without impairing the compaction quality.
For the first lifting process after ballasting by means of the ballast train, it is advantageous if the track panel is lifted by at least 50 mm, particularly by at least 70 mm. This means that only a small lift is required for the final second tamping process in order to produce the predefined track geometry.
Advantageously, the track panel is lifted during the second lifting process with a lift in a range between 15 mm and 25 mm, particularly in a range between 20 mm and 25 mm. This provides sufficient scope for producing the predefined track geometry without unnecessarily loosening the ballast bed.
The method is further developed by an advantageous deep tamping process in which, after the first lifting process, by means of the deep tamping unit a first tamping process is carried out in a lower depth layer of the ballast bed with vibrating and squeezing tamping tines, and a second tamping process is carried out in an upper depth layer of the ballast bed with the same tamping tines. During the tamping processes, the track panel is held in position by means of a lifting unit.
The efficiency of the method according to the invention is further increased if the tamping process is carried out after the second lifting process by means of a multi-sleeper tamping unit. In this way, the second tamping process is completed with increased working speed.
The maintenance speed is further increased if the tamping work is carried out with a tamping machine integrated into a cleaning train. In this case, the cleaning process and the respective compaction process are synchronized with each other by means of a higher-level control system. Additionally, all units are supplied via a shared power wagon of the cleaning train, with an optimized energy supply of the integrated machines.
In the following, the invention is explained by way of example with reference to the accompanying figures. The following figures show in schematic illustrations:
By means of lifting devices 9, the track panel 5 is lifted and held in position while a ballast removal device 10 removes the ballast 1 with a removal height h1 (e.g. 300 mm). This defined removal height h1 extends from the formation 3 to be exposed to the lower edges of the sleepers 6 supported in the ballast bed 4. Of course, the ballast 1 located between the sleepers 6 is also picked up. Usually, the ballast removal device 10 comprises a revolving endless excavating chain which continuously picks up the ballast 1 while moving forward and transfers it to a conveyor device for forwarding to a screening unit.
A further conveyor device delivers the cleaned ballast 1 to a ballast placement device 11. In relation to a working direction 12, a first layer of the cleaned ballast 1 is placed on the exposed formation 3 immediately behind the removal device 10 by means of this ballast placement device 11. A plough 13 is used to distribute the placed ballast 1 with a desired first bed height h2 (e.g. 150 mm) on the formation 3.
The track panel 5 placed on this newly created ballast bed 4 is set into vibration under load by means of a stabilizing unit 14. This stabilizing process controls settlements of the ballast bed 4 beforehand. The result is a reduced second bed height h3 (e.g. approx. 130 mm).
In the second work phase, a further layer of ballast is dumped onto the track 2 by means of a ballast train 15. A ballast plough 16, preferably designed as a separate machine, distributes the ballast 1 with adjustable plough blades 17. This means that there is sufficient ballast 1 on and between the sleepers 6 for a first tamping process.
A tamping machine 18 provided for this purpose comprises a lifting unit 19 and a tamping unit 20. The lifting unit 19 lifts the track panel 5 with a first lift h4 (e.g. 80 mm) to a third bed height h5 (e.g. 210 mm). Then a stabilizing machine 21, also called a Dynamic Track Stabilizer, is used. This stabilizer is either designed as a separate machine or coupled with the tamping machine 18. The effect of the stabilizing unit 14 leads to a compaction of the ballast bed 4 to a fourth bed height h6 (e.g. 205 mm).
The work steps of the second work phase repeat themselves in a third work phase, with a third layer of ballast being placed in the track 2 by means of a ballast train 15. Subsequently, the track panel 5 is first lifted to a fifth bed height (e.g. 285 mm) with a second lift h7 (e.g. 80 mm). After fixing by means of the tamping unit 20, a slight lowering to a sixth bed height h9 (e.g. 280 mm) is again carried out by means of the stabilizing unit 14.
Subsequently, in a third tamping process, the track panel 5 is brought into a predefined track geometry with a third lift h10 (e.g. 20 mm to 25 mm). The final track position is set after a final stabilization by means of the stabilizing unit 14. The ballast bed 4 renewed in this way has approximately the same height as before the cleaning process. The disadvantage of this known method is the large number of work steps that are necessary due to the layered ballast placement including ballast compaction.
The method according to the invention reduces the work steps without decreasing the quality of the cleaned ballast bed 4. The new sequence of work steps is explained with reference to
As before, the cleaning of a ballast bed 4 starts with a cleaning machine 8. A lifting unit 9 of the cleaning machine 8 lifts a section of the track panel 5 to be treated. For this purpose, the lifting unit 9 comprises roller clamps which clasp the respective rail head of the rails 7 and roll along the rails 7 while the cleaning machine 8 moves forward.
A ballast removal device 10 with a crossbeam running below the lifted track panel section picks up the ballast 1 with a predefined removal height h1 (e.g. 300 mm). Specifically, the ballast is picked up by means of an endless excavating chain that surrounds the track panel 5. Via a lateral channel, the excavating chain conveys the removed ballast 1 upwards to a first conveyor device not shown. In this way, the ballast 1 is fed to a screening unit arranged on the cleaning machine 8.
The ballast 1 is cleaned in the screening unit. If necessary, the edges are then sharpened in an impact mill. The cleaned ballast 1 is conveyed to the ballast placement device 11 by means of a further conveyor device. If there is not enough treated ballast 1, it is supplemented with new ballast 1. This is carried along, for example, in a storage unit of the cleaning machine 1. New ballast 1 can also be carried along with so-called material conveyor and hopper units (MFS). These units are rail vehicles coupled to the cleaning machine 8 and are used to pick up spoil produced during ballast cleaning.
According to the invention, the ballast placement device 11 of the cleaning machine 8 places considerably more ballast 1 in the track 2 than before. The ballast layer smoothed by the plough 13 of the cleaning machine 8 advantageously has a first bed height h2′ of 250 mm, measured from the exposed formation 3 to the lower edges of the sleepers 6. A stabilizing unit 14 integrated into the cleaning machine 8 compacts the ballast bed 4 to a second bed height h3′ (approx. 230 mm).
In a second work phase, new ballast 1 is discharged onto the track 2 by means of a ballast train 15. A ballast plough 16 distributes this ballast 1 for a subsequent tamping process. In this, a lifting unit 19 of a tamping machine 18 lifts the track panel 5 with a first lift h4′ by advantageously 70 mm. This achieves a third bed height h5′ of approx. 300 mm.
According to the present invention, the fixing of the track panel 5 in this lifted position is carried out in two steps by means of a deep tamping unit 22. Such a unit 22 is disclosed in AT 522237 A1 of the same applicant. Compared to a conventional tamping unit 20, the deep tamping unit 22 has a larger vertical range of movement of the tamping tool carrier. Additionally, longer tamping tines 23 are used.
In a first step, the tamping tines 23 of the deep tamping unit 22 penetrate a lower depth layer of the ballast bed 4 and are squeezed there in a vibrating manner. In this case, the upper edges of the tine plates located at the tamping tine ends are at least 100 mm below the lower edges of the sleepers 6. Advantageously, the vibration is generated by means of a rotating eccentric shaft to which hydraulic squeezing cylinders are connected. The squeezing movement and vibration can also be superimposed in the respective hydraulic cylinder; a corresponding actuation with integrated displacement measuring is to be provided.
To achieve the predefined squeezing forces and squeezing times, it must be ensured that the pressure applied by the squeezing cylinders is adjusted during deep tamping. The pressure setting must be adjusted so that the same forces and times are reached during deep tamping as during subsequent normal tamping. If necessary, the overall compaction result is positively influenced if the tamping tines 23 are only set into vibration during the first compaction step. A squeezing process is eliminated.
This is immediately followed by a second compaction step in which the tamping tines 23 are lowered into an upper depth layer of the ballast bed 4. There, a squeezing process is carried out under application of vibration. This upper depth layer lies between the previously compacted lower depth layer and the lower edges of the sleepers 6. In this way, the ballast bed 4 is compacted over the entire bed height h5′ by means of the deep tamping unit 22. This is followed by a stabilizing process using a stabilizing machine 21, which results in a slightly reduced bed height h6′ (approx. 295 mm).
The final geometry of the track 2 will be produced in a final work phase. In the process, the track 2 is treated with the same or a further tamping machine 18. A lifting and lining unit 19 lifts the track panel 5 with a slight overlifting compared to the predefined track geometry. This takes into account the subsequent track settlement during stabilization. This second lift h7′ is in the range of 20 mm to 25 mm and is thus significantly lower than the first lift h4′. Additionally, the track panel 5 is laterally lined.
A tamping unit 20 for the simultaneous tamping of several sleepers 6 reduces the maintenance time in this work phase. This tamping unit 20 is arranged either in addition to the deep tamping unit 22 on the same tamping machine 18 or on a separate tamping machine 18. In the first case, the same lifting and lining unit 19 is advantageously used for all lifting steps. Finally, a stabilizing process takes place by means of a stabilizing unit 14. This is arranged either in a separate stabilizing machine 21 or on a machine frame coupled with the tamping machine 18.
The new method of work is not limited to the exemplary plain-line cleaning method shown. In particular, the method according to the invention is applicable to cleaning trains with integrated tamping machines 18 and stabilizing machines 21 and, if necessary, plough blades 17. The method can also be used for cleaning turnouts or replacing turnouts. Here too, ballast up to a bed height h2′ of 250 mm is placed at once and then compacted in one pass with deep tamping, normal tamping, and stabilizing.
| Number | Date | Country | Kind |
|---|---|---|---|
| A50182/2021 | Mar 2021 | AT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/053936 | 2/17/2022 | WO |
