Measurement and Analysis of Lengthwise Rail Shock
A shock pulse is defined by Cyril M. Harris in Shock & Vibration Handbook as "a substantial disturbance characterized by a rise of acceleration from a constant value and decay of acceleration to a constant value in a short period of time." Lengthwise shocks occur in normal rail handling as a result of yard classification of cars and train slack action. The result of rail shock can be quite graphic in terms of lading damage. But shock characteristics and their measurement is the subject of frequent debate; i.e. just what is a 'substantial disturbance' and a 'short period of time?' And the advent of programmable shock machines to conduct laboratory analysis of product response to shock has made the need for accurate pulse portrayal imperative. This study evaluated a variety of rail cars in attempt to define meaningful parameters.
The purpose of this study is to define significant attributes in the measurement and analysis of rail shock accelerations.
The purpose of this study is to define significant attributes in the measurement and analysis of rail shock accelerations. Rail shocks resulting from yard switching of cars were measured under a variety of circumstances, some controlled, some not. Measurements were taken from both standard draft gear cars and cushioned cars. Impact speed was recorded for each impact measured. Car body accelerations were measured at a sample rate of 256 samples per second, analog filtered at 60 Hz. For analysis, the measured acceleration time histories were both low pass and band pass filtered to evaluate significant frequency components.