Under sleeper pad

1. An under sleeper pad for fastening to a bottom side, situated opposite the rails, of a track sleeper, the under sleeper pad comprising at least one elastic layer including cork grains, arranged in a distributed manner therein, of a cork granulate, and at least one cellular synthetic elastomer, said at least one cellular synthetic elastomer is foamed.

2. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer in the elastic layer forms a matrix in which the cork grains, arranged in a distributed manner, of the cork granulate are embedded, and the cellular synthetic elastomer connects the cork grains to one another.

3. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer in the elastic layer is in the form of grains which are arranged in a distributed manner and comprised of the cellular synthetic elastomer, and the grains comprised of the cellular synthetic elastomer and the cork grains of the cork granulate are connected to one another by at least one binder.

4. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer has a porosity in the range of 10% to 90%.

5. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer has a density in the range of 200 kg/m 3 to 1000 kg/m 3 .

6. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer has a compression set of at most 10%.

7. The under sleeper pad as claimed in claim 1 , wherein the cellular synthetic elastomer as the solid matter of the elastomer comprises at least one of polyurethane, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, ethylene-propylene-diene rubber, chloroprene rubber, silicone, or polyisoprene.

8. The under sleeper pad as claimed in claim 1 , further comprising a connecting layer on a top side, provided for connection to the track sleeper.

9. The under sleeper pad as claimed in claim 1 , wherein the elastic layer has a thickness in the range of 5 mm to 20 mm.

10. An arrangement comprising a track sleeper and the under sleeper pad as claimed in claim 1 , the under sleeper pad is fastened to a bottom side, situated opposite the rails, of the track sleeper.

11. The arrangement of claim 10 , wherein the under sleeper pad includes a connecting layer that is cast into the track sleeper.

12. The under sleeper pad as claimed in claim 1 , further comprising a textile protective layer on a base side, facing an underlying surface in an operating position, of the under sleeper pad.

13. The under sleeper pad as claimed in claim 12 , wherein the textile protective layer is a nonwoven layer.