Abstract: A counterweight is provided for tensioning the wire of a catenary in a railway line, comprising a metal shell (1) made up of a frame (1a) and a surrounding body (1b) which is filled with a filler material (2), which integrates at least high-density concrete in combination with a metal material as an additional filler for increasing the density of the counterweight. The frame (1a) is embedded into the filler material (2) and in turn, is linked to the surrounding body (1b) by a welded joint.

Abstract: Each filler piece (1) for an elevator counter-weight, the subject matter of the invention, comprises a central metal core (5) and a concrete casing (4), such that a piece (1) is obtained having a target density whose value is comprised between 4 and 5.5 g/cm3 by combining the concrete of the casing (4) and the central metal core (5). The percentages by weight of metal material in the core (5) and concrete in the casing (4) are a function of the target density to be reached in each piece (1), said percentages are determined by a relationship between the density of the concrete of the casing (4), the density of the metal material of the core (5) and the target density of the piece (1).