Ultrasound is commonly used to detect structural damage in rail infrastructure, but current technology is not useful for safety-critical crossing points. An EU initiative delivered the much-needed inspection system.
The coarse grain structure of high-manganese-content crossings creates
significant beam scatter, leading to low sensitivity and false alarms.
So-called frogs are critical to rail safety as they are the location at
which railway cars change direction. For the same reason, they are also
the point of frequent explosive impact collisions from rolling stock.
Early detection of fatigue and cracks is of utmost importance to passenger safety and maintenance operator profitability. The EU-funded SAFTINSPECT
(Ultrasonic synthetic aperture focusing technique for inspection of railway crossings (frogs)) project sought to develop an affordable and reliable ultrasonic inspection solution for sections of high-manganese steel rail crossing points used in European railways.
Project partners successfully designed, developed and manufactured a fully automated ultrasonic inspection system that inspects flaws in high-manganese-content crossings. The technology consists of several key components, namely a 4-axis scanner, probe holder and irrigation system, ultrasonic transducer, ultrasonic pulser-receiver, desktop PC, scanner control software and synthetic aperture focusing technique software.
The system was tested and validated in the laboratory and on the field during freezing temperatures by using components that contained real crack defects. The system was able to successfully detect and size subsurface cracking at the critical nose region of the crossings. It also performed well under adverse weather conditions, and electrical interference from overhead power lines did not reveal any negative effects.
SAFTINSPECT's in-line volumetric inspection technology for railway frogs will significantly reduce the costs and health risks for railway operators and maintenance contractors. It is a technology long overdue and will no doubt be welcomed by industry and consumers alike.
The SAFTINSPECT consortium is now seeking rail track operators to provide track access to enable full qualification of the technology on a large number of frog crossings and well as funding opportunities for system commercialisation.