Reivindicaciones

1. High-speed railway aerodynamic sleeper (1) comprising: - one central area (2), - two support areas (3), on each side of the central area (2), on which rails (13) are placed, - two outer areas (4), located at the ends of the sleeper (1), and following the support areas (3), wherein the cross-section of the sleeper (1) comprises, on the central area (2), and on the support areas (3), and on the two outer areas (4), two solid sections: - a first bottom section (5), comprising a first polygon (7) of at least 4 sides, - a second top section (6), comprising at least one second polygon (8) of "n" sides, with n ≥ 4; such that: - the first bottom section (5) and the second top section (6) are attached, and the top base (9) of the first polygon (7) and the bottom base (10) of the second polygon (8) share their sides;characterized in that the central area (2) of the sleeper (1) comprises: - one middle sector (2a) that constitutes the centre of the sleeper (1), and - two end sectors (2b) located at both sides of the middle sector (2a) of the central area (2) of the sleeper (1), such that the cross-section comprises in the second top section (6) of the middle sector (2a) only one second polygon (8) in which the number of sides "n" is comprised between 4 and infinity, such that by means of the geometry of the sleeper (1) the speed of the wind at the ballast height in the area between sleepers is reduced. 2. High-speed railway aerodynamic sleeper (1), according to claim 1,characterized in that in the middle sector (2a) of the central area (2) the number of sides "n" of the second polygon (8) tends to infinity, having a conic section profile. 3. High-speed railway aerodynamic sleeper (1), according to claim 1,characterized in that, being the number of sides of the second polygon (8) "n" equal to 4, the cross-section of the sleeper (1) in the end sectors (2b) of the central area (2), comprises a third polygon (12) located over the second polygon (8), the third polygon having (12) at least "m" sides, with m ≥ 4. 4. High-speed railway aerodynamic sleeper (1), according to claim 3,characterized in that, in the end sectors (2b) of the central area (2), the number of sides "m" of the third polygon (12) tends to infinity, having a conic section profile. 5. High-speed railway aerodynamic sleeper (1), according to any of claims 3 or 4,characterized in that, on the top section (6), the top sides (14) of the second polygon (8) of the middle sector (2a) of the central area (2) are a continuation of the top sides (14') of the third polygon (12) in the end sector (2b) of the central area (2), having continuity at the outer surface offered by the third polygon (12) and the second polygon (8). 6. High-speed railway aerodynamic sleeper (1), according to claim 1,characterized in that the number of sides "n" of the second polygon (8) being equal to 4 in the middle sector (2a) of the central area (2), the length of the top side (14) of the second polygon (8) is less than or equal to half the length of the bottom base (10) of said second polygon (8). 7. High-speed railway aerodynamic sleeper (1), according to claim 1,characterized in that there is a line (11), longitudinally, in the sleeper (1) that marks a transition between the first bottom section (5) and the second top section (6) and the inclination of the line (11) varies according to its location in the three areas of the sleeper (1), said sleeper (1) offering continuity at the outer surface. 8. High-speed railway aerodynamic sleeper (1), according to any of the previous claims,characterized in that it is made of concrete. 9. High-speed railway aerodynamic sleeper (1), according to any one of claims 1 to 7,characterized in that it is made of composite materials.