Methods and devices for locating a railway vehicle

1. A method for locating a railway vehicle, comprising:

measuring an acoustic signature of a railway vehicle passing over a railway switch, using a distributed acoustic sensing apparatus including an optical fiber sensor placed along the railway switch, the railway switch being connected, on one side, to a first section of a first railway track and, on the other side, to a second section of the first railway track and to a second railway track, the railway switch being configured for switching between a first position, in which rails of the first section and rails of the second section are linked, and a second position, in which the rails of the first section and rails of the second railway track are linked, the second railway track diverging from the first railway track;

analyzing the measured acoustic signature, using an electronic processing unit, by identifying, in the measured acoustic signature, vibration patterns representative of track geometry and/or track curvature; and

determining a track occupancy information, representative of which of the first railway track or the second railway track is occupied by the railway vehicle, using the electronic processing unit, based on the identified vibration patterns,

wherein said identifying vibration patterns comprises detecting a vibration pattern representative of the railway vehicle going along a curved track portion of the switch leading to the diverging second railway track, the railway vehicle being then determined as occupying the second railway track, and

wherein said detecting comprises identifying a first portion of the acoustic signature in which signal amplitude values are associated to a signal amplitude level higher than the signal amplitude level of a second portion of the acoustic signature, said first portion including:

first and second sub-regions each associated to a first signal frequency value, and

a third sub-region between the first and second sub-regions, said third sub-region being associated to a second signal frequency value lower than the first signal frequency value.

2. The method of claim 1 , wherein the method further comprises:

recording the determined track occupancy information into a machine-readable storage medium.

3. The method of claim 1 , wherein said identifying vibrations patterns further comprises comparing, using the electronic processing unit, at least a portion of the measured acoustic signature with predetermined reference data.

4. A device for locating a railway vehicle, comprising:

a distributed acoustic sensing apparatus including an optical fiber sensor placed along a railway switch, the railway switch being connected, on one side, to a first section of a first railway track and, on the other side, to a second section of the first railway track and to a second railway track, the railway switch being configured for switching between a first position, in which rails of the first section and rails of the second section are linked, and a second position, in which the rails of the first section and rails of the second railway track are linked, the second railway track diverging from the first railway track; and

an electronic processing unit having an input connected to the distributed acoustic sensing apparatus,

wherein the electronic processing unit is configured for:

receiving an acoustic signature measured by the distributed acoustic sensing apparatus, the acoustic signature having been measured during the passage of a railway vehicle over the railway switch,

analyzing the measured acoustic signature by identifying, in the measured acoustic signature, vibration patterns representative of track geometry and/or track curvature,

determining a track occupancy information, representative of which of the first railway track or the second railway track is occupied by the railway vehicle, based on the identified vibration patterns,

wherein said identifying vibration patterns comprises detecting a vibration pattern representative of the railway vehicle going along a curved track portion of the switch leading to the diverging second railway track, the railway vehicle being then determined as occupying the second railway track, and

wherein said detecting comprises identifying a first portion of the acoustic signature in which signal amplitude values are associated to a signal amplitude level higher than the signal amplitude level of a second portion of the acoustic signature, said first portion including:

first and second sub-regions each associated to a first signal frequency value, and

a third sub-region between the first and second sub-regions, said third sub-region being associated to a second signal frequency value lower than the first signal frequency value.

5. The device of claim 4 , wherein the electronic processing unit is further configured for recording the determined track occupancy information into a machine-readable storage medium.

6. The device of claim 4 , wherein said identifying vibrations patterns further comprises comparing, using the electronic processing unit, at least a portion of the measured acoustic signature with predetermined reference data.