ROLLING CONTACT FATIGUE ON TRAMWAY’S RAIL
Last modified: 2017-02-28
slip protection equipment. On those sections, where other types of the carriages also run, the defects were less frequent. Measurements of eventual defects were performed using Eddy current sensor, digital microscope, wheel mounted inertial sensor and high-speed camera.
Measurements with Eddy current sensors were carried out on the running surface of rail. They did not show cracks but average depth of defects could be determined. Surface deformations were detected by a digital microscope and their dimensions were also measured. Images
made by digital microscope (from “micro-slip”) showed similarity to the “comet-shaped” rail surface corrugation caused by high-intensity acceleration (“macro-slip”). Based on this fact, the author assumed that probably the slip plays an important role in the formation of defects. Slip values recorded by a high-speed camera during start and stop of tram carriages were found equivalent to the length of the defect under consideration. Further investigations were made to determine the exact value of the slip during the start and stop of the tram carriage under operating conditions. For that purpose, wheel- and vehicle-mounted accelerometers and the speed acquisition device of the tram carriage were used. Assessing the results of the experiments, it is concluded, that the wheel slip is responsible for the defects discovered, but further investigations are needed.