The sleeper has a rigid block (11) with two vertical openings (16) traversing the block on both sides from its upper side to its base. A base plate (13) has an elastic pad (12) on which the block is placed, and vertically extending rods (15), where each rod is housed in each opening. Each of multiple pre-stressing devices (17) is mounted around the rod inside the opening. The devices apply preset pre-stressing effort on the pad.
