Perspectives on railway track geometry condition monitoring from in-service railway vehicles

Abstract

This paper presents a view of the current state of monitoring track geometry condition from in-service vehicles. It considers technology used to provide condition monitoring; some issues of processing and the determination of location; how things have evolved over the past decade; and what is being, or could/should be done in future research. Monitoring railway track geometry from an in-service vehicle is an attractive proposition that has become a reality in the past decade. However, this is only the beginning. Seeing the same track over and over again provides an opportunity for observing track geometry degradation that can potentially be used to inform maintenance decisions. Furthermore, it is possible to extend the use of track condition information to identify if maintenance is effective, and to monitor the degradation of individual faults such as dipped joints. There are full unattended track geometry measurement systems running on in-service vehicles in the UK and elsewhere around the world, feeding their geometry measurements into large databases. These data can be retrieved, but little is currently done with the data other than the generation of reports of track geometry that exceeds predefined thresholds. There are examples of simpler systems that measure some track geometry parameters more or less directly and accurately, but forego parameters such as gauge. Additionally, there are experimental systems that use mathematics and models to infer track geometry using data from sensors placed on an in-service vehicle. Finally, there are systems that do not claim to measure track geometry, but monitor some other quantity such as ride quality or bogie acceleration to infer poor track geometry without explicitly measuring it.

Measurement of Railway Track Geometry: A State-of-the-Art Review

“…Typically a tachometer measures the rotation speed of a non-driven axle belonging to a wheel set usually in revolution/minute. British railway engineers, Weston et al (2015Weston et al ( :p.1064, have asserted that "The speed of rotation of an unpowered wheel and the odometer is the integration of the tachometer with respect to time multiplied by the wheel circumference to convert rotations per unit time into distance.". Distance measurement of a traveling vehicle is done in a direct way applying distance sensors.…”

“…It should be noted that it is hard to measure the movements, say, only into the vertical direction, since the ends of the sensor will surely have certain lateral and longitudinal displacements as well. In this respect, Weston et al (2015Weston et al ( :p.1066 reported that "The capacitative or the inductive displacement sensors are more robust but can only measure small displacements. ".…”

“…In recent years, considerable research has been done in many countries related to condition monitoring of railway track geometry and investigating the performance of riding quality. Among others, in the paper of Weston et al (2015), authors presented an excellent overview about the current developments of such systems installed on board of railway coaches running in regular operation all over the country in Great Britain. A detailed reasearch was reported from Japan about the use of a vertical displacement measuring system mounted on the bogie and supplemented by an additional sensor from the bogie to the axlebox to monitor rail geometry (Yazawa and Takeshita, 2002).…”

A contribution for integrated analysis of railway track performance at transition zones and other discontinuities

“…Despite past effort to understand the complex behaviour of railway tracks, enhance its performance [9][10][11][12] and develop tools to help in the asset management process [13][14][15][16] needed on the relationship between the characteristics of the train-track system and the development of track geometry defects [17]. Previous studies focused mostly on the influence of track geometry defects on the vehicle dynamics, in terms of ride comfort and derailment risk [3,14,[18][19][20][21][22], while others focused on the wheel-rail interface [23][24][25].…”

Track geometry estimation of a conventional railway from car-body acceleration measurement

“…Monitoring of railway track geometry from an 'in-service' vehicle has become an increasingly attractive proposition over the past decade (Weston et al, 2015). Track geometry measurement systems using in-service vehicles has been developed around the world but they are still in an early developmental phase.…”