Track Twist Monitoring

Abstract

The twist of a railway track ( 36 ) can be measured with a vehicle which includes a frame ( 25 ). This frame ( 25 ) carries a roll sensor ( 40 ) to measure the rate of roll (w) about a longitudinal axis, and sensors ( 38 ) to monitor the variations in the relative tilt between the frame ( 25 ) and the rails ( 35 ). The signals from these sensors ( 38 ) and ( 40 ) enable the changes in cant (Δc) between one instant and the next to be determined, and so the twist of the track can be calculated by summing successive changes in cant. This method of determining twist can operate at substantially any vehicle speed, and gives consistent measurements in real-time.

1 . Equipment for monitoring twist of railway tracks, the equipment comprising a vehicle including a frame, and sensors on the frame comprising a roll sensor to measure the rate of roll about a longitudinal axis, and sensors to monitor the variations in relative tilt between the frame and the rails, a sensor to monitor distance traveled, means to sample data from the sensors, and means to determine from the sampled data the twist of a railway track. 
   
   
       2 . Equipment as claimed in  claim 1  wherein the frame forms at least part of a bogie of the vehicle. 
   
   
       3 . Equipment as claimed in  claim 1  wherein the frame forms at least part of a body of the vehicle. 
   
   
       4 . A method for monitoring twist of railway tracks, the method using a vehicle with a frame, the method comprising measuring the distance traveled by the vehicle, measuring the changes in lateral tilt of the frame between successive positions along the track, subtracting therefrom measured changes in the tilt of the frame relative to the rails, and so deducing the change in cant, and from successive deduced changes in cant determining the twist of the railway track. 
   
   
       5 . A method as claimed in  claim 4  wherein the measurement data are sampled at sufficiently short intervals that there are several samples per metre of vehicle travel along the track. 
   
   
       6 . A method as claimed in  claim 5  wherein there are at least eight samples per metre. 
   
   
       7 . A method as claimed in  claim 4  also comprising marking locations of excessive twist values using a marking device, in real time. 
   
   
       8 . A dedicated track monitoring vehicle incorporating equipment for monitoring twist of railway tracks by a method as claimed in  claims 4 . 
   
   
       9 . (canceled) 
   
   
       10 . A method as claimed in  claim 5  also comprising marking locations of excessive twist values using a marking device, in real time.