SUSPENDED RAIL FASTENING APPARATUS

The present invention relates to railway rail fastening apparatus for suspending a railway rail above a rail foundation.

EP 0758418B discloses railway rail fastening apparatus for suspending a railway rail at discrete locations along its length above a rail foundation. As shown in Figures IA and IB of the accompanying drawings, this apparatus comprises a baseplate 3' having a rail seat region 20' above which a railway rail 1 is suspended when the apparatus is in use and two shoulders 4' located one on each side of the rail seat region 20' . The apparatus further comprises two rail suspending assemblies 5' located when in use one on each side of the rail 1, each assembly 5' comprising an elastic member 6' for supporting the head 100 of the rail 1 on one side thereof, a bracket 7' for applying a lateral clamping force to the elastic member β' , a wedge member 8' located when in use between associated one of the shoulders 4' and the bracket 7' for maintaining the lateral clamping force, and a clip 9' for securing the wedge member 8 'on the shoulder 4'.

An important factor in such a suspended railway rail apparatus is the degree to which the apparatus resists longitudinal creep of the railway rail therethrough.

Although the performance of the apparatus disclosed in EP 0758418B is very good in this regard, improved performance would be an advantage.

According to an embodiment of the present invention there is provided railway rail fastening apparatus for suspending a railway rail at discrete locations along its length above a rail foundation, the apparatus comprising: two rail suspending assemblies located when in use one on each side of the rail, each assembly comprising an elastic

member for supporting the head of the rail on one side thereof and a bracket for applying a lateral clamping force to the elastic member; wherein the rail suspending assembly on one side of the rail seat region is located such that the centre line of the assembly is offset with respect to that of the rail suspending assembly on the other side of the rail by x mm along the longitudinal axis of the rail, where x is 50≥x>0 mm.

The apparatus may further comprise two shoulders, located one on each side of a rail seat region of the rail foundation, above which the railway rail is suspended when the apparatus in use, each rail suspending assembly further comprising a wedge member located when in use between an associated one of the shoulders and the bracket of that assembly, thereby to maintain the said lateral clamping force. In this case, the rail suspending assembly and shoulder on one side of the rail seat region are located such that the centre line of the assembly and shoulder is offset with respect to that of the rail suspending assembly and shoulder on the other side of the rail seat region by x mm along the longitudinal axis of the rail, where x is 50≥x>0 mm.

Desirably, x is 30≥x>0mm, and preferably x is 30>x≥10mm. Even more desirably, x is 25≥x>0mm, more preferably x is 25≥x≥10mm, and even more preferably x=25mm.

Surprisingly, providing a longitudinal offset of a limited distance between the centre line of the rail suspending assembly on one side of the rail seat region with respect to that of the rail suspending assembly on the other side of the rail seat region provides improved resistance to creep of the rail. For example, if there is no offset at all, the longitudinal resistance to creep is 14.76 kN for a particular assembly, whereas an offset of 25mm provides increased resistance to creep of 16.95kN, but at an offset of 90mm creep resistance is negligible.

Reference will now be made, by way of example, to the

accompanying drawings, in which:

Figures IA and IB (described above) show plan and part cross-sectional views respectively of conventional suspended rail fastening apparatus; and Figures 2A to 2D show respective plan, part cross- sectional, side and perspective views of a railway rail fastening apparatus embodying the present invention.

Apparatus embodying the present invention comprises two shoulders 4A, 4B located one on each side of a rail seat region 20 of a rail foundation 2. A railway rail 1 is suspended above the rail seat region 20 by means of two rail suspending assemblies 5A, 5B located one on each side of the rail 1, each assembly 5A, 5B comprising an elastic member 6 made of rubber or similar material for supporting the head 100 of the rail 1 on one side thereof, a bracket 7 for applying a lateral clamping force to the elastic member 6, and a wedge member 8 located when in use between an associated one of the shoulders 4A, 4B and bracket 7 for maintaining the lateral clamping force. The wedge member 8, which preferably has a serrated face which engages with a serrated face on a rail-facing surface of the associated shoulder 4A, 4B is held in place within the assembly 5 by means of a clip 9. The clip 9 comprises an approximately U-shaped bar of round cross-section which, in use, lies in a substantially vertical plane. Figure 2A shows that a centre line CL _A of the rail suspending assembly 5A and shoulder 4A on one side of the rail 1 is offset along the longitudinal axis of the rail 1 from the centre line CL _B of the rail suspending assembly 5B and shoulder 4B on the other side of the rail 1.

Figures 2A to 2D illustrate an embodiment in which the shoulders 4 hook in to a baseplate 3 which is secured to the rail foundation 2 by two offset bolts 35. This is advantageous, since such a baseplate may be retro-fitted to an existing rail foundation already having two offset bolt- receiving holes. However, it is also advantageous to employ an embodiment of the invention in a new rail

installation, with or without a baseplate.