A rail pad comprises a membrane (3) from opposite faces of which there project protrusions (4, 5), which may be ribs, possibly extending along the pad, perhaps over its whole length, or studs. The protrusions are such that no line perpendicular to the membrane passes through more than one of the protrusions. The pad is such that it is stiffer on one side than the other, for example because the ratio between the total area of protruding material and the total area of membrane free of protrusions ...