Patent Application
20070267511
Preferred embodiments of the invention will now be described, by way of example only, with reference to the following drawings in which:
It should be noted that the drawings are not to scale, and certain features have been emphasised for the sake of clarity. It should also be noted that the cross-sectional views shown in
The invention provides a sleeper in which a slot is formed in an upper surface thereof. The slot defines an oblique passage for cables crossing a railway track supported by the sleeper. The oblique angle of the passage maximises the cable capacity of the slot. Rail fastening members are provided on opposite sides of the slot for different rails of the railway track. By providing the rail fastening members on opposite sides of the slot, loads transmitted from rail vehicles to the sleeper are balanced.
Referring to the drawings, the sleeper 1 according to the invention is a folded structure formed from 12 mm thick sheet steel. The sleeper structure comprises a base 3, two sides 5a, 5b, and an upper surface. The overall dimensions of the sleeper structure are approximately 2500 mm length, 280 mm width and 185 mm height. The sleeper 1 is galvanised to provide protection from corrosion.
The upper surface of the sleeper structure is defined by two portions 7a, 7b separated by an elongate gap 9. The elongate gap 9 has a constant width along most of the length of the sleeper, the edges of the gap 9 defining an oblique angle of 2.5 degrees with the sides 5a, 5b. At the ends of the sleeper 1 the edges of the gap 9 diverge slightly, one of the edges of the gap 9 being parallel with the sides 5a, 5b.
The portions 7a, 7b of the upper surface provide respective wide surfaces at the ends of the sleeper 1. A wedge shaped rail fastening member 19a, 19b is attached to each of these wide surfaces. The rail fastening member 19a, 19b are positioned for fastening the spaced apart rails of the railway track (not shown). The rail fastening member 19a, 19b are welded to the sleeper structure and each has a pair of holes formed therein for fastening the rails to the sleeper 1.
The portions 7a, 7b of the upper surface also provide respective narrow surfaces at the ends of the sleeper 1. A wedge shaped rail supporting member 21a, 21b is attached to each of these narrow surfaces. The rail supporting members 21a, 21b are much smaller than the rail fastening members 19a, 19b and provide support for the rails without any fastening function. The rail supporting members 21a, 21b are welded to the sleeper structure.
Thus, in the above described arrangement, the portions 7a, 7b of the upper surface each include a rail fastening member 19a, 19b at one end of the sleeper 1 (the wide end) and a rail supporting member at the other end of the sleeper 1 (the narrow end). One rail fastening member 19a, 19b and one rail supporting member 21a, 21b are provided for each rail.
The sides 5a, 5b and the portions 7a, 7b of the upper surface of the sleeper 1 together define an elongate slot for accommodating cables 11, for example, signalling cables.
By providing portions 7a, 7b having a wide end and a narrow end, sufficient space may be provided (at the wide end) for attaching the rail fastening members 19a, 19b. The oblique angle of the gap 9 also maximises the size of cables 11 that may be laid in the elongate slot.
Reinforcing brackets 23a, 23b are provided directly underneath each of the rail fastening members 19a, 19b. The reinforcing brackets 23a, 23b each comprise a piece of steel sheet bent at a right angle and of similar thickness to the sleeper structure. The reinforcing brackets 23a, 23b are each positioned such that the side of the bracket defining the right angle faces into the slot, and the limbs of the bracket 23a, 23b bridge the corners of the sleeper structure, as shown in the cross-sectional views of
The reinforcing brackets 23a, 23b provide additional bracing in the region of the rail fastening members 19a, 19b, which is where stresses in the sleeper 1 are greatest. However, the angled design of the brackets 23a, 23b ensures that they do not protrude into the elongate slot excessively.
The base 3 has a number of holes 15 formed therein to allow moisture to drain from the inside of the sleeper structure. End plates 17a, 17b are also welded to the ends of the sleeper structure. The end plates 17a, 17b do not substantially restrict the passage of the cables 11.
When a rail vehicle travels over the rails 25, stresses are transferred into the sleeper through the rail fastening plates 19a, 19b. The reinforcing brackets 23a, 23b help to absorb these stresses.
The sleeper and railway track arrangement described above are specific embodiments of the invention. Various modifications and changes, within the scope of the claims, will be apparent to the skilled person.
For example, the sleeper described above is formed from sheet steel. However, in certain embodiments, the sleeper may be moulded from other materials, such as concrete.
