Nondestructive Evaluation on Bogie Frames of Overage Railway Vehicles

초록

The railway safety act and its enforcement regulation (ministry decree) has prescribed that railway operators shall use their all vehicles in the term of the use stipulated as to the vehicle types in Korea, where 30 years for high speed train and freight wagon, 25 years for metro including light rail and passenger rolling stock, and 20 years for locomotives. It has also provided that the safety diagnosis shall be done to extend the term of the use for an overage railway vehicles, which contains dimension measurement and nondestructive inspection of car body and bogie frame, electric diagnostics for high voltage lines, running performance (acoustic noise, ride comfort and vibrational characteristics), and estimate of expected life cycle of car body and bogie frame. On the basis of diagnostic results, the designated institute for the safety diagnosis can extend the term to maximum 15 years. For the railway vehicles to have additional term more than 5 years, railway operators shall perform the safety diagnostics for themselves every additional 5 year which shall be equivalent to that of designated institute. For urban rail vehicles (metro) approaching to the term of the use (25 years), in this paper, magnetic-particle inspection was performed on surface of welded parts in bogie frames. An ultrasonic inspection was added in the welded parts to have linear crack more than 30mm. Considering the results of the nondestructive inspections, qualitative methodology was proposed to select which vehicle might have worst conditions to investigate the expected life cycle of bogie frames.