An assembly for mounting a longitudinally extending track on a substrate has a track plate having a top face adapted to carry the track and formed unitarily below the top face with a plurality of longitudinally extending tongues, a base plate at least partially below the track plate, adapted to be anchored to the substrate, horizontally surrounding the tongues of the track plate, and formed with a plurality of longitudinally extending tongues transversely spaced from, longitudinally interleaved with, and horizontally at least partially level with the tongues of the track plate. The track plate and base plate are wholly out of direct engagement with and spaced vertically and/or horizontally from each other. An elastic jacket or liner is engaged between the plates and between the tongues of the track plate and the tongues of the base plate.