Method of Measuring Wheel and Rail Contact Forces and Derailment Quotients Continuously. Development of a Measuring Device.

Abstract

Oscillatory wheel load fluctuation of considerable amplitude is almost always observed on Shinkansen vehicles running at high speed. >From the acceleration measured on the axlebox, the frequency of this fluctuation is estimated to be approximately 50 to 70 Hz. Using the conventional measuring method, continuous outputs of wheel load can not be obtained, so it is difficult to investigate such a high frequency phenomenon precisely. We have developed a new method of measuring the forces and derailment quotients continuously, using two pairs of strain gage bridges whose output phases are shifted by π/2, and summing up the outputs with a weighting functiom This method is available for measuring the forces between wheel and rail up to about 100 Hz. In the running test of Shinkansen, it was confirmed that the wheel load fluctuation was related to the axlebox acceleration generated through small irregularities on the rail surface, and that more accurate derailment quotients than those obtained by conventional way could be measured continuously up to 425 km/h by means of the new device.