Train-based differential eddy current sensor system for rail fastener detection

Abstract

One of the crucial components in rail tracks is the rail fastening system, which acts as a means of fixing rails to the sleepers to maintain the track gauge and stability. Manual inspection and 2D visual inspection of fastening systems have predominated over the past two decades. However, both methods have drawbacks when visibility is obscured and are found to be relatively expensive in terms of cost and track possession. The present article presents the concept of a train-based differential eddy current (EC) sensor system for fastener detection. The sensor uses the principle of electromagnetic induction, where an alternating-current-carrying coil is used to create an EC on the rail and other electrically conductive material in the vicinity and a pick-up coil is used to measure the returning field. This paper gives an insight into the theoretical background and application of the proposed differential EC sensor system for the condition monitoring system of rail fasteners and shows experimental results from both laboratory and field measurements. The field measurements were carried out along a heavy-haul railway line in the north of Sweden. Results obtained from both the field measurements and from the lab tests reveal that that the proposed method was able to detect an individual fastening system from a height of 65 mm above the rail. Furthermore, missing clamps within a fastening system are detected by analysing a time domain feature of the measurement signal.

Condition Monitoring of Rail Transport Systems: A Bibliometric Performance Analysis and Systematic Literature Review

“…Its significant function is connected to maintaining the track gauge and stability. In Chandran et al [ 233 ], the authors took into consideration the monitoring of rail fastening conditions with the use of an eddy current sensor system for fastener detection. This kind of sensor applies the principle of electromagnetic induction.…”

An Investigation of Railway Fastener Detection Using Image Processing and Augmented Deep Learning

“…In Sweden, the tracks are covered with snow for the majority of the year and would thus require additional rail surface treatment or a removal process that adds to the expenses of the railroad companies. One possible solution to overcome this difficulty and ensure safe, sustainable and reliable rail operation, is by combining automated visual inspection with non-destructive testing such as eddy current sensors [6,33] for fastener inspection. The presence of non-conductive materials (such as ballast and snow) in the sensor-to-target gap do not affect the eddy current sensors.…”

Limitations of eddy current inspection for the characterization of near-surface cracks in railheads

“…In this study, this probe was used for measuring near-surface cracks in a railhead, as they are commonly used by rail maintainers to inspect rail track. [47][48][49] In the probe, there are two coils used to inspect cracks, as shown in figure 1(a). Both the coils generate magnetic fields with opposite directions to one another.…”