A direction-fixation mount secures a track assembly to a flat upper surface of a fixed substrate. The track assembly includes a flat plate having a pair of opposite end edges, a track sitting on the plate, and fasteners securing the track to the plate. The direct-fixation mounting assembly has an elastomeric pad of predetermined stiffness underneath the plate and atop the surface so that the track and plate bears downward via the pad on the surface, and a pair of end restraints each having a rigid outer part fixed to the substrate offset outward from a respective one of the end edges of the plate, a rigid inner part spaced inward from the outer part and fixed to the respective outer end edge of the plate, and an elastomeric mass separate from the pad and fixed to and between the respective inner and outer parts.