Shaped under sleeper pad

Abstract

A shaped under-deck pad in the form of a plate, substantially corresponding in shape and size to a railway sleeper, made of flexible material, provided with profiled working surfaces, wherein the surface facing the sleeper is provided with periodically repeated grooves, transverse to the pad extension, while the surface facing the ballast is provided with regular irregularities in the form of alternating spherical protrusions and recesses arranged in rows, obliquely in relation to the axis of the pad extension, wherein the rows are shifted relative to each other by half the wavelength, wherein the protrusions and recesses flow into each other in an undulating manner and the transitions in the cross-section are substantially sinusoidal in shape, characterized in that the wavelength (a) is at least equal to the average value of the average grain size of the ballast sub-ballast,and the amplitude (b) is at least equal to the average value of the minimum grain size of the ballast, but not greater than the average value of the average grain size of the ballast.,