a lower plate on which there is placed

an upper plate, and

an outer shoulder, located at each end of the plates, comprising means for anchoring the fastening on a support surface, wherein:

the plates and the outer shoulders are attached to one another by an adhesive, thereby forming a single-block assembly,

the upper plate comprises a smooth central segment located between two grooved areas located in correspondence with the ends of the upper plate,

the fastening comprising two inner shoulders comprising lower grooves which can engage and fit into a plurality of positions on the grooved areas of the upper plate, where said inner shoulders comprise means for housing and securing an elastic fastening clip for fastening a railway rail; and

wherein the upper plate further comprises a longitudinal channel running from one grooved area to the opposite grooved area and passing through the smooth central segment, where the inner shoulders in correspondence with the lower grooves comprise a guide bridge-like channel.