An assembly for mounting a longitudinally extending track (T) on a substrate (S), the assembly, wherein longitudinal refers to a horizontal extension of the track (T), comprising: a track plate (10; 10') having a top face (10a; 10a') adapted to carry the track (T), a base plate (20; 20') adapted to be anchored to the substrate (S), the base plate having a planar bottom face (20a; 20a') adapted to sit flatly on the substrate (S), and an elastic jacket , characterized in that the track plate (10; 10') is formed unitarily below the top face (10a; 10a') with a plurality of longitudinally extending tongues (10d; 10d'); in that the base plate (20; 20') is horizontally surrounding the tongues (10d; 10d') of the track plate (10; 10'), and is formed with a plurality of longitudinally extending tongues (20d; 20d') transversely spaced from and longitudinally and horizontally interleaved with the tongues (10d; 10d') of the track plate (10; 10'), the track plate (10; 10') and base plate (20; 20') being wholly out of direct engagement with and spaced vertically or horizontally from each other; and in that the elastic jacket (30; 30') is engaged between the track and base plates (10, 20; 10', 20') and between the tongues (10d; 10d') of the track plate (10; 10') and the tongues (20d; 20d') of the base plate (20; 20') and having a lower face that, in an unstressed condition of the jacket (30; 30'), is at least partially spaced above the bottom face (20a; 20a') of the base plate (20; 20'), whereby, in a mounted state of the assembly, when the base plate is anchored to the substrate (S), downward movement of the track plate (10; 10') relative to the substrate (S) stresses the jacket (30; 30') in shear between the tongues (10d, 20d; 10d', 20d') of the track plate and the tongues of the base plate and, after a predetermined short downward movement, compresses the jacket (30; 30') between the track plate and the substrate (S). a track plate (10; 10') having a top face (10a; 10a') adapted to carry the track (T), a base plate (20; 20') adapted to be anchored to the substrate (S), the base plate having a planar bottom face (20a; 20a') adapted to sit flatly on the substrate (S), and an elastic jacket , characterized in that the track plate (10; 10') is formed unitarily below the top face (10a; 10a') with a plurality of longitudinally extending tongues (10d; 10d'); in that the base plate (20; 20') is horizontally surrounding the tongues (10d; 10d') of the track plate (10; 10'), and is formed with a plurality of longitudinally extending tongues (20d; 20d') transversely spaced from and longitudinally and horizontally interleaved with the tongues (10d; 10d') of the track plate (10; 10'), the track plate (10; 10') and base plate (20; 20') being wholly out of direct engagement with and spaced vertically or horizontally from each other; and in that the elastic jacket (30; 30') is engaged between the track and base plates (10, 20; 10', 20') and between the tongues (10d; 10d') of the track plate (10; 10') and the tongues (20d; 20d') of the base plate (20; 20') and having a lower face that, in an unstressed condition of the jacket (30; 30'), is at least partially spaced above the bottom face (20a; 20a') of the base plate (20; 20'), whereby, in a mounted state of the assembly, when the base plate is anchored to the substrate (S), downward movement of the track plate (10; 10') relative to the substrate (S) stresses the jacket (30; 30') in shear between the tongues (10d, 20d; 10d', 20d') of the track plate and the tongues of the base plate and, after a predetermined short downward movement, compresses the jacket (30; 30') between the track plate and the substrate (S). <EOS>