Remote condition monitoring of structural integrity of rails and crossings

In-service rails and cast manganese crossings may develop structural defects due to the stresses and environmental conditions they are subjected to. Currently, depending on the severity of damage, a defective rail or crossing can remain in service with or without repairs being carried out or replaced within a standardised time-schedule after an Emergency Speed Restriction (ESR) has been imposed. For certain defects, the application of fish plates or clamps may be necessary to ensure that at least theoretically the defect is not growing further during passage of the trains even though the ESR has been imposed. However, to further lower the cost and delay incurred by faults found in railway network, predictive maintenance is gradually becoming the preferred solution and there is increasing need for a sound technique to be employed to assess the integrity of the railway infrastructures precisely. Acoustic emission (AE) has been widely used for structure health monitoring and is also a promising tool for the remote evaluation of the structural integrity of in-service rails and crossings. Laboratory and field tests carried showed that the use of acoustic emission together with appropriate signal processing algorithms can provide an insight on the presence of damage and severity in in-service rails and crossings.