Method and controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track
Disclosed is a method for determining the relationship between a track-circuit current signal and a railway vehicle location, including: sending, by a track circuit, current signal across a railway track block; measuring the current signal for different railway vehicles running successively on the railway track block; aligning the measured current signals and calculating a reference curve as the average value of all the aligned curves by using a Dynamic Time Warping algorithm, this reference curve representing the relationship between the track-circuit current signal and the railway vehicle location on the railway track block.
1. Method for determining the relationship between a track-circuit current signal and a railway vehicle location, comprising
sending, by a track circuit, current signal across a railway track block,
measuring the current signal for different railway vehicles running successively on the railway track block;
aligning said measured current signals and calculating a reference curve (R) as the average value of all the aligned curves by using a Dynamic Time Warping algorithm, this reference curve (R) representing the relationship between the measured track-circuit current signal and the railway vehicle location on said railway track block.
2. The method of claim 1 , wherein the inputs of the Dynamic Time Warping algorithm are a plurality of current signals measured for several railway vehicle move sequences across the railway track block and a maximum number of algorithm iterations (N), wherein each current signal measured for an individual (i th ) railway vehicle move sequence (I i ) contains transmitted current peak values (I (i,j) ) of a plurality of samples of said measured track-circuit current signal.
3. The method of claim 2 , wherein the reference curve (R) contains a plurality of elements (r 1 , r 2 , . . . , r p ).
4. The method of claim 3 , comprising the steps of:
a) initializing ( 2 ) the elements of the reference curve (R) by randomly selecting one current signal measured for an individual railway vehicle move sequence;
b) for each current signal measured for an individual railway vehicle move sequence performing ( 5 ) the Dynamic Time Warping algorithm between the current signal and the reference curve;
c) for each element (p th ) in the reference curve, associating ( 6 ) an appropriate set of elements from the current signal measured for an individual railway vehicle move sequence with said element (p th ) in the reference curve;
d) updating ( 8 ) each element (p th ) of the reference curve by calculating the average of all associated elements found in step c);
e) repeating steps a) to d) by initializing ( 2 ) the elements of the reference curve (R) with the elements of the updated reference curve calculated at step d), up to the maximum number of algorithm iterations (N).
5. The method of claim 4 , further comprising the steps of determining a confidence interval and/or a safety margin using a bootstrap percentiles method.
6. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 4 .
7. The method of claim 3 , further comprising the steps of determining a confidence interval and/or a safety margin using a bootstrap percentiles method.
8. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 3 .
9. The method of claim 2 , further comprising the steps of determining a confidence interval and/or a safety margin using a bootstrap percentiles method.
10. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 2 .
11. The method of claim 1 , further comprising the steps of determining a confidence interval and/or a safety margin using a bootstrap percentiles method.
12. The method of claim 11 , comprising the steps of:
collecting ( 100 ) transmitted current values measured for N railway vehicle moves, thus obtaining a railway vehicle move data set;
creating ( 102 ) a plurality of bootstrap railway vehicle move datasets ( 102 ′, 102 ″, 102 ′″, . . . , 102 B) of size N by resampling the original railway vehicle move data set with a replacement set, wherein resampling is performed by random selecting railway vehicle moves from the original set with probability of 1/N;
calculating ( 104 ) the reference curve ( 104 ′, 104 ″, 104 ′″, 104 B ) for each bootstrap dataset.
13. The method of claim 12 , comprising the step of:
determining, on the basis of the reference curves ( 104 ′, 104 ″, 104 ′″, 104 B) obtained for each bootstrap dataset, using a predetermined percentile interval, lower Ri(Tx) and upper Ru(Tx) confidence interval values for predefined measured track-circuit current values Tx.
14. The method of claim 13 , comprising the step of:
setting ( 106 ) a safety margin in function of the mean value of the lower (Ri(Tx)) confidence interval values.
15. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 14 .
16. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 13 .
17. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 12 .
18. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 11 .
19. Controller for determining the relationship between a track-circuit transmitted current signal and a railway vehicle location on a railway track, the controller being adapted to be connected to a track circuit arranged to send a current signal across a railway track block on which different railway vehicles are running successively, the controller being arranged to perform the method according to claim 1 .
20. Track circuit comprising a controller according to claim 19 .