Development of novel acoustic emission techniques for monitoring the structural health of cast manganese crossings

A vital component of switch and crossing (S&C) systems are the cast manganese noses. Cast manganese steel normally contains 11 - 14% of manganese. It has a predominantly large austenitic microstructure providing significant resistance to impact and wear damage. In-service crossing inspections are carried out using visual and liquid penetrant inspection. Accessibility and geographical constraints normally prohibit the use of time-consuming inspection techniques. A team consisting of researchers from NR Projects, Maintenance and the University of Birmingham are collaborating to develop an efficient acoustic emission (AE) technique for monitoring the structural health of crossings in real time. The customised AE system under development has been tested under laboratory and field conditions. Results show that detection of damage propagation is possible by mounting piezoelectric AE sensors on the crossing. Structural health information obtained from the crossing can be used to optimise the maintenance decisionmaking process and optimise availability and reliability of rail infrastructure. The key results obtained during testing of samples in the laboratory and instrumented in-service crossings at sites on the West Coast Main Line (Willesden and Wembley) and on the Chilterns line (Hatton) are presented in summary. The findings of this study support the implementation of predictive railway maintenance practice.