The invention relates to a method which enables sleepers to be produced for the railway track superstructure having optimised performance characteristics, in a reliable and cost-effective manner. The method according to the invention provides the following production steps: a) providing a mixture 10-60 % mass of which consists of a granulate of a plastic, which is deformable by applying heat, and the remainder of which consists of a sand having a bulk density of 1.4-2.0 g/cm.sup.3; b) heating the mixture to a temperature of 150-200 C.; c) pouring the mixture into a press mould reproducing the sleeper; d) pressing the mixture in the mould at a pressing pressure measured in the mixture of 1-5 MPa over a pressing period of up to 60 minutes; and e) removing the sleeper from the mould.

The invention relates to a method which enables sleepers to be produced for the railway track superstructure having optimised performance characteristics, in a reliable and cost-effective manner. The method according to the invention provides the following production steps: a) providing a mixture 10-60 % mass of which consists of a granulate of a plastic, which is deformable by applying heat, and the remainder of which consists of a sand having a bulk density of 1.4-2.0 g/cm.sup.3; b) heating the mixture to a temperature of 150-200 C.; c) pouring the mixture into a press mould reproducing the sleeper; d) pressing the mixture in the mould at a pressing pressure measured in the mixture of 1-5 MPa over a pressing period of up to 60 minutes; and e) removing the sleeper from the mould.

A railroad tie formed of a polymeric or polymeric composite material and configured for enhanced mechanical interaction with an underlying ballast. The tie includes at least a top longitudinal surface, a pair of side longitudinal surfaces, a bottom longitudinal surface, and two end faces. At least the bottom longitudinal surface includes a plurality of indentations formed along a length thereof. Additionally, the tie includes at least one serrated edge portion having a plurality of serrations, the at least one serrated edge portion formed along at least part of the longitudinal length of the tie at an edge between at least one of the side longitudinal surfaces and the bottom longitudinal surface to provide for enhanced mechanical interaction with the ballast.

Natural fiber composite construction materials including boards, siding, railroad ties, standing seam roofing panels, roofing panels that support solar-electric modules, and roofing panels that support vegetation are provided. In various embodiments, composite construction materials comprise about 50-60% kenaf fiber.

Natural fiber composite construction materials including boards, siding, railroad ties, standing seam roofing panels, roofing panels that support solar-electric modules, and roofing panels that support vegetation are provided. In various embodiments, composite construction materials comprise about 50-60% kenaf fiber.

The present invention describes a railroad sleeper (1) for fixation of at least a pair of rails (2,2) of a railroad network, comprising a contact surface (3), wherein each rail of the pair of rails (2,2) is fixed spaced apart from each other, the railroad sleeper (1) being configured by comprising a hollow sector (4) delimited by association of the contact surface (3) with the anchorage walls (5,5), thus establishing a free portion (17) adjacent to the anchorage walls (5,5) and opposite the contact surface (3). The present invention further describes an embodiment in which the hollow sector (4) of the railroad sleeper is delimited by a support surface and the process of manufacturing a railroad sleeper.

The present invention describes a railroad sleeper (1) for fixation of at least a pair of rails (2,2) of a railroad network, comprising a contact surface (3), wherein each rail of the pair of rails (2,2) is fixed spaced apart from each other, the railroad sleeper (1) being configured by comprising a hollow sector (4) delimited by association of the contact surface (3) with the anchorage walls (5,5), thus establishing a free portion (17) adjacent to the anchorage walls (5,5) and opposite the contact surface (3). The present invention further describes an embodiment in which the hollow sector (4) of the railroad sleeper is delimited by a support surface and the process of manufacturing a railroad sleeper.

A composite railway sleeper (1; 50; 100) comprising an outer coating shell (2; 51; 101) made of composite plastic material and a shaped structural core (3; 52; 102), made of a material comprising at least concrete contained within said outer coating shell (2; 51; 510; 101), wherein said outer coating shell (2; 51; 510; 101) presents in the upper outer face (2a; 51a; 101a) two distinct and opposite groups of grooves (4; 53) suitable to receive the angular guide plates (G) belonging to pre-assembled elastic type fastening systems (64) for the connection of two respective rails (R) with said railway sleeper (1; 50; 100).

A composite railway sleeper (1; 50; 100) comprising an outer coating shell (2; 51; 101) made of composite plastic material and a shaped structural core (3; 52; 102), made of a material comprising at least concrete contained within said outer coating shell (2; 51; 510; 101), wherein said outer coating shell (2; 51; 510; 101) presents in the upper outer face (2a; 51a; 101a) two distinct and opposite groups of grooves (4; 53) suitable to receive the angular guide plates (G) belonging to pre-assembled elastic type fastening systems (64) for the connection of two respective rails (R) with said railway sleeper (1; 50; 100).

A fiber-reinforced rigid polyurethane foam composite railway sleeper with high fiber content and a manufacturing method thereof. The railway sleeper is formed by bonding a plurality of fiber-reinforced rigid polyurethane foam composite boards with high fiber content by a binder, and the outer surface of the railway sleeper is provided with an anticorrosive paint film. The fiber-reinforced rigid polyurethane foam composite boards with high fiber content include a polyurethane resin as a matrix material and a fiber as a reinforcing material. The problem of insufficient impregnation of the polyurethane and the fiber is solved by using a plurality of technical means such as using a mixed polyether polyol having a low hydroxyl value and a low functionality, using a coupling agent, etc., thus a fiber-reinforced rigid polyurethane foam composite product having a density higher than 840 kg/m.sup.3 and a fiber content greater than 60% is manufactured.