Measurements of the vibrational behaviour of railway track are presented. Because the track system is effectively infinite, its motion consists of propagating waves, and usual modal analysis concepts and techniques are not appropriate. New experimental techniques are therefore developed to handle these phenomena. In particular the various propagating vibrational waves in the rail are identified in terms of their complex propagation coefficients and their corresponding deformed shapes. These waves are separated by using an analysis based on fitting a series of complex exponential functions to the measured data. Some predictions of wave phenomena in track are also presented for comparison and good agreement between theory and experiment is found. © 1997 Academic Press Limited.