Non-destructive Assessment and Health Monitoring of Railway Infrastructures

A continuous increase in the worldwide demand for high-speed traffic, freight tonnage as well as of the train operating frequency is worsening the decay conditions of many railway infrastructures. This occurrence affects economy-related business as well as contributing to rising maintenance costs. It is known that a failure of a railway track may result in tremendous economic losses, legal liabilities, service interruptions and, eventually, fatalities. Parallel to this, requirements to maintain acceptable operational standards are very demanding. In addition to the above, a main issue nowadays in railway engineering is a general lack of funds to allow safety and comfort of the operations as well as a proper maintenance regime of the infrastructures. This is mostly the result of a traditional approach that, on average, tends to invest in high-priority costs, such as safety-related costs, compromising lower-priority interventions (e.g., quality and comfort of the operations). A solution to correct this trend can be moving from a reactive to a proactive action planning approach in order to limit more effectively the likelihood of progressive rail track decay. Within this context, this paper reports a review on the use of traditional and non-destructive testing (NDT) methods for the assessment and health monitoring of railway infrastructures. State-of-the-art research on a stand-alone use of NDT methods or a combination of them for quality control, inspection and maintenance tasks in this subject area is discussed.