Transforming rail profile inspections
A mobile test bench for rail profile inspection during rail grinding and milling.
Australia’s railway network comprises metro lines for commuters and heavy-haul lines for transport, services and freight from remote locations. The sheer size of the Australian landscape provides a variety of conditions and challenges for proper maintenance to ensure smooth and efficient operations.
These rail systems are constantly subjected to high load, excessive residual stresses and extreme weather conditions. These causes contribute to the deformation of the rail head and increased rail wear, which combine to cause an elevated noise level and damage the track components. In addition, it also causes defects from rolling contact fatigue which can drastically reduce the rail lifespan. Rail industry now demands increased yearly availability with a longer rail lifecycle and better environmental sustainability. Therefore, there is an increasing urge to develop a reliable track maintenance system to ensure the availability of track all year round.
Rail maintenance services such as rail grinding and rail milling are commonly used rail maintenance techniques to reduce the damage from rolling contact fatigue and eliminate elevated noise levels. The development of integrated sensors and testing instruments have enabled continuous and automated data logging and measurement and eliminated the need for manual on-track measurement.
Bestech Australia has supplied sensors, instrumentation and data acquisition to support the development of a holistic testing and measurement system for the rail testing and rail maintenance industry. We supply the laser profile scanner from Micro Epsilon for the Australian Rail Consultant to develop a high precision scanning system for rail wear maintenance.
Grinding and milling
The practice of rail grinding and milling is to ensure the removal of sufficient materials as necessary to guarantee the maximum lifespan of the rail. Therefore, it is essential to measure the profile before and immediately after the grinding wheel. Rail milling trains are generally used for track repair and maintenance. The scanCONTROL scanner can be placed at the position before and after the grinding wheel. This configuration allows automatic recording of data and transmission to the central control unit in the milling train.
The scanCONTROL profile scanner differs from other equivalent profile scanning technology. The sensor has an intelligent and integrated controller which allows automatic evaluation of profile properties in the sensor such as gap, groove, tile angle, etc. It saves time for the operators as they do not need to develop a specific algorithm to process the raw profile and measurement results to define the rail condition. This smart scanner provides an option to intelligently track the profile on the specific area on the rail head. It can also automatically align itself to correct the inclination and position to generate a smoother profile.
However, there is also an option to use a scanner without the smart intelligent controller. This sensor will output the raw profile in the measurement software. The users can use the data with a powerful, integrated software development kit based on C/C++, LabVIEW, Linux or VB. Effective rail track maintenance also extends to predictive maintenance based on condition monitoring applications. The profile scanner also has been used to develop automated condition monitoring systems which are mounted on the measurement wagon / test bogie.
For example, measurement wagons are commonly used for inline rail inspection. Six laser profile scanners are installed on the measurement wagon to measure rail profile from below, above and from the side, on each side of the rail gauge.
This system is possible as the scanners can be synchronised and can record all the profiles within one measurement.
Therefore, profiles, width and height of the rails on both sides are simultaneously evaluated and determined in the sensors.
The scanners have been proven to measure reliably under changing environmental conditions such as on fast changing surfaces. This is due to the advanced real-time-surface-compensation feature that compensates for the change in the intensity of the reflected light. It allows the detector to adapt the exposure time and the threshold of the light detection in real-time to generate stable results.
Sensing technologies have been crucial in supporting the advanced testing and industrial R&D as well as product development such as we have seen for the rail testing and condition monitoring applications.
Not only for rail track maintenance, but there are also numerous applications where sensors can be integrated directly on the rail cars for guiding and drive systems or to control the position of the coupling in the locomotives.