The present invention provides a high-hardness sponge railroad tie which is a thermoplastic resin foam, wherein the density of the foam is 0.1-0.85, and the hardness of the foam is shore A 70 - shore D 70.

The invention relates to polyurethane foam-forming composition possessing modified silicone surfactants and having delayed catalysis for modifying foam hardness and improved foam openness.

The tension adjustment mechanism (5) adjusts the hardness of the cushion foam (1) by adjusting the tension of the band (41) consisting of a flexible material.

We have different grades that will allow you to modify the hardness of the PU foam produced.

The present invention provides a high-hardness sponge railroad tie which is a thermoplastic resin foam, wherein the density of the foam is 0.1-0.85, and the hardness of the foam is shore A 70 - shore D 70.

This soft polyurethane foam shows only a small change in hardness when the temperature changes.

The foam core has a higher hardness and a higher density than the outer layer.

The center portion is formed of a first foam material having a first hardness.

The center portion is formed of a first foam material having a first hardness.

The invention relates to polyurethane foam-forming composition possessing modified silicone surfactants and having delayed catalysis for modifying foam hardness and improved foam openness.

Totally neutral for the skin, the foam has a scale of appropriate hardness.

The side portions are formed of a second foam material having a second hardness.

They are partly supplemented by Shore-00-hardness (rarely Shore-O-hardness) for cellular rubber.

The side portions are formed of a second foam material having a second hardness.

The section (2') of the supporting structure (1) made of metal foam or made of the hollow body filled with metal foam is therefore significantly lighter at the same rigidity than a conventional section of a supporting structure.