A system for vertically displacing masses, comprising: (a) a drive assembly comprising at least one bi-directional rotary machine driving at least one drive pulley, said drive assembly being located at an upper level of a vertical displacement space; (b) a plurality of cable loops (260, 260') connecting the drive assembly with a transfer assembly comprising at least one transfer pulley, said transfer assembly being located at a lower level of said vertical displacement space, wherein said transfer assembly maintains tension in the cable loops (260, 260'), wherein the portion of cable of each cable loop (260, 260') disposed between the drive pulley and the transfer pulley defines a first portion of cable and the remaining portion of cable of each cable loop (260, 260') disposed between the drive pulley and the transfer pulley defines a second portion of cable; (c) each portion of cable (260a, 260b) comprises a plurality of coupling assemblies (261a, 261b, 261a', 261b'); (d) a plurality of masses (300a, 300b) that are attached by means of said coupling assemblies (261a, 261b, 261a', 261b') to the portions of cable (260a, 260b) to be displaced through the vertical displacement space; (e) an upper assembly for deflecting cable loops comprising a plurality of upper deflector pulleys and a lower assembly for deflecting cable loops comprising a plurality of lower deflector pulleys, wherein said assemblies for deflecting cable loops (230, 250) are displaceable between two positions, a first position wherein the first portion of cable is substantially centred in the vertical displacement space, and a second position wherein the second portion of cable is substantially centred in the vertical displacement space. (a) a drive assembly comprising at least one bi-directional rotary machine driving at least one drive pulley, said drive assembly being located at an upper level of a vertical displacement space; (b) a plurality of cable loops (260, 260') connecting the drive assembly with a transfer assembly comprising at least one transfer pulley, said transfer assembly being located at a lower level of said vertical displacement space, wherein said transfer assembly maintains tension in the cable loops (260, 260'), wherein the portion of cable of each cable loop (260, 260') disposed between the drive pulley and the transfer pulley defines a first portion of cable and the remaining portion of cable of each cable loop (260, 260') disposed between the drive pulley and the transfer pulley defines a second portion of cable; (c) each portion of cable (260a, 260b) comprises a plurality of coupling assemblies (261a, 261b, 261a', 261b'); (d) a plurality of masses (300a, 300b) that are attached by means of said coupling assemblies (261a, 261b, 261a', 261b') to the portions of cable (260a, 260b) to be displaced through the vertical displacement space; (e) an upper assembly for deflecting cable loops comprising a plurality of upper deflector pulleys and a lower assembly for deflecting cable loops comprising a plurality of lower deflector pulleys, wherein said assemblies for deflecting cable loops (230, 250) are displaceable between two positions, a first position wherein the first portion of cable is substantially centred in the vertical displacement space, and a second position wherein the second portion of cable is substantially centred in the vertical displacement space.