The purpose of this tensioner is to release the tension in the track rails due to the expansions and contractions caused by the variation of temperature in the different seasons of the year.
The work of the tensioner consists of tying two consecutive sections of rail by subjecting them to a tensile force to bring the adjacent edges of such sections closer together, tending to join them until leaving a narrow space corresponding to a previously placed welding cleat, to then proceed to welding and joining of both rail sections by means of said welding cleats. This leaves both rail sections subject to a controlled traction force that will be maintained after dismantling the hydraulic tensioner with an elongation of such rail sections.
It has two tie-down blocks associated with a pair of hydraulic cylinders and longitudinal tie-rods. These tie-blocks have a centered channeling, whose bottom rests on the tread of the head of two consecutive sections of a track rail, also incorporating wedges to secure the fastening of such tie blocks.