A fastening mechanism for coupling track rail to a substrate comprising: a fastener body formed by a metallic base having a central rail-supporting core and an overmolded non-metallic coating encasing the metallic base, the fastener body including a horizontally extending lower side, and a horizontally extending upper side having a rail support surface extending fore and aft between a front edge and a back edge of the fastener body, and laterally between a left outboard edge and a right outboard edge of the fastener body; a first metallic pillar positioned at a first location laterally between the rail support surface and the left outboard edge, and a second metallic pillar positioned at a second location laterally between the rail support surface and the right outboard edge; the first metallic pillar and the second metallic pillar defining a first vertically extending bore and a second vertically extending bore, respectively, and each of the first vertically extending bore and the second vertically extending bore communicating between the lower side and the upper side of the fastener body and being structured to receive an anchor held fast within the substrate and coupled to the corresponding first metallic pillar or second metallic pillar; the overmolded non-metallic coating extending peripherally around each of the first metallic pillar and the second metallic pillar to position vibration-attenuating non-metallic material of the coating between the metallic base and each of the first metallic pillar and the second metallic pillar; and the overmolded non-metallic coating including one or a plurality of pads (56, 57) positioned adjacent to and vertically below the rail-supporting core and formed by non-metallic material. a fastener body formed by a metallic base having a central rail-supporting core and an overmolded non-metallic coating encasing the metallic base, the fastener body including a horizontally extending lower side, and a horizontally extending upper side having a rail support surface extending fore and aft between a front edge and a back edge of the fastener body, and laterally between a left outboard edge and a right outboard edge of the fastener body; a first metallic pillar positioned at a first location laterally between the rail support surface and the left outboard edge, and a second metallic pillar positioned at a second location laterally between the rail support surface and the right outboard edge; the first metallic pillar and the second metallic pillar defining a first vertically extending bore and a second vertically extending bore, respectively, and each of the first vertically extending bore and the second vertically extending bore communicating between the lower side and the upper side of the fastener body and being structured to receive an anchor held fast within the substrate and coupled to the corresponding first metallic pillar or second metallic pillar; the overmolded non-metallic coating extending peripherally around each of the first metallic pillar and the second metallic pillar to position vibration-attenuating non-metallic material of the coating between the metallic base and each of the first metallic pillar and the second metallic pillar; and the overmolded non-metallic coating including one or a plurality of pads (56, 57) positioned adjacent to and vertically below the rail-supporting core and formed by non-metallic material.