Applications

Application areas of nondestructive testing

The reliability and safety of railway operations - especially on high-speed and heavily loaded track sections - are determined by a combination of factors, among which timely detection of rail defects is one of the most critical. During operation, rails are subjected to significant dynamic loads and high stresses in the wheel-rail contact zone, leading to the development of metal contact fatigue. Even minor internal discontinuities or surface damage under such conditions can evolve into critical defects and significantly increase the risk of rail fracture. Effective non-destructive testing (rail flaw detection) of rails makes it possible to detect such hazardous flaws at early stages and prevent their progression to a critical level.

The safety of railway operations across the globe relies significantly on the quality and integrity of the railway tracks. Tracks in good condition serve as the foundation for safe and reliable transportation, reducing the likelihood of accidents and ensuring smooth operations. Achieving and maintaining such safety standards in the most efficient and cost-effective manner involves the implementation of Risk-Based Engineering principles. These principles provide a structured framework for assessing and mitigating potential risks associated with railway tracks.

Manual rail inspection on the track is used in two scenarios:

  • As a confirmatory inspection of defects detected during continuous rail inspection using single-rail and double-rail flaw detectors or, in some cases, high-speed ultrasonic rail inspection systems.
  • As an acceptance inspection of aluminothermic welded rail joints.

The middle link in the rail track quality management system (in the part of ultrasonic rail inspection) is the rails ultrasonic testing using hand-pushed ultrasonic rail inspection trolleys, also known as ultrasonic single-rail and dual-rail flaw detectors. This is the most widespread class of equipment used on all railways in the world.

The systems of OKOSCAN-73HS family can be mounted on different chassis depending on end user`s requirements. A railway car or a hi-rail truck with truck bed will allow using large monitors and comfortable conditions for operators` work which is essential during continuous inspection of large railway track areas. Usage of hi-rail trucks is the most universal option because it allows to start and finish inspection at any rail/road crossing. This helps to plan inspection in the areas with busy train traffic.

The safety of movement on any railway track in the world depends on the quality of the railway track. The most cost effective solution is following the Risk Based Engineering principles which requires correct and up-to-date information about all rails in the railway tracks. Detection and further monitoring of the technical state of rails with operational defects allow their timely replacement. One of the main components of the rails defects detection approaches is ultrasonic rail inspection, which allows detection of both surface and inner defects in the whole rail cross section (except for the rail base wings).

Both the manufacture defects – the ones that appear in the process of production – and in-service defects of fatigue type may develop (fig.1) in various metal products. The cracks may develop at different angles to the surface growing to considerable depths thus causing the threat of a product breaking when in service.