This research developed a precision measurement system using a laser to measure and evaluate the straightness of rail welding part and implemented an algorithm to obtain the maximum, minimum, maximum/minimum difference and QI values based on the rail surface shape data measured using the development system. In addition, the performance of the straightness measurement system and algorithm of the development rail welding part was evaluated by comparing the results of the commercial equipment RailProf and RailStraight.
The rail welding part straightness measurement and evaluation system developed through this research was developed based on a precision laser to compensate for the shortcomings of measurement error caused by rail property change (material, temperature change) using the existing eddy current technique. In addition, the development system can measure surface opening defects within the measurement area (including welding parts) because it can measure changes in surface shape as well as 0.5mm of data to increase rail shape measurement accuracy. In addition, the field application plan for the rail head surface condition evaluation equipment developed based on laser was presented as follows.
First, Article 23 (Rail Polishing) of the track maintenance guideline was newly established to perform rail polishing when the rail surface quality index (QI) value exceeds 1 when measuring the unevenness of the rail welding part using a straightness tester, and the first equation to calculate the rail surface quality index was derived as follows.
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Second, rail welding is performed by measuring torsion and high torsion using laser-based rail head condition evaluation equipment developed in this study instead of the existing 1m straight and gap gauge, and rail quality management with increased accuracy is suggested.
In order for rail quality management to proceed with systematic rail management in the future, it is necessary to actively utilize the track maintenance guidelines based on this paper and the results of field application research when manufacturing pole rails and polishing rail welds.
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