The technical development of rail vehicles and rail track systems raised the requirements of inspections of the track. The increase of the traction force of the vehicles and the production and use of harder steel types for the rails change the quality requirements of maintenance and inspection. Where it was sufficient to have skilled personnel to walk along the track in the past, nowadays elaborate measurement technology is necessary to detect flaws in the rail.
The current state of modern industrial surface inspection systems allows the application of modern technology and new solutions to detect flaws. The use of optical line sensors, spatial and temporal high resolution, modern light techniques and actual FPGA components enables surface inspection systems to have an accuracy around one tenth of a millimetre. Preliminary investigations have shown that some critical rail surface states, like micro cracks, can only be assessed at this high resolution. To cope with the resulting data rate, one has to assess the optical data at a very early stage in order to store only potentially risky surface conditions which have to be evaluated carefully offline.
Actual scientific research has shown that the present development of urban traffic causes new types of flaws on the rail which were unknown so far. The standard inspection systems using ultrasound are not able to detect this type of flaw in an early stage. But this is necessary as one can avoid heavy subsequent damage through simple actions like welding or grinding the rail. To do so the flaws have to be recognized automatically and their geo location has to be known. Moreover, a frequent observation of the surface makes the development of the flaw visible and allows for the ability to make conclusions about where critical rail conditions originate.
This project aims for the development of an optical rail scanner that allows the inspection of the rails surface and the documentation of its evolution.
Within the project, the following steps were carried out:
- Analysis of the surface characteristic of flaws on the rails
- Selection of the required hardware and software for surface inspection
- Creation of a test setup in the laboratory
- Field test of the measuring device on a hand-held Cart
- Adjustments to the requirements of a vehicle-based measuring device, and a first test under realistic conditions
- Analysis of the collected data using complex surface inspection software
Within the fractINSPECT project, the following milestones and key results have been achieved:
- A prototype of the measuring device on a hand-held cart was developed
- In a second step, a prototype for the usage on a track vehicle was successfully implemented
- A robust data basis for forecasting and algorithm development
- A robust measuring system prototype, adapted to the needs of urban transport and measurement vehicles
- Continuous measurement with the measuring vehicle of the Vienna transportation Company (Wiener Linien GmbH & Co KG)
- Algorithms for detecting Spallings and microcracks have been developed and implemented
- After the successful implementation of the prototype system, extensive rail surface monitoring activities were carried out.
Findings of the study are published in a final presentation (short version, German only) which is available online via the Federal Ministry for Transport, Innovation and Technology (BMVIT) at: