GB2185510A - Railway level crossing panel - Google Patents

Abstract

The railway level crossing panel (10) comprising polyester concrete, coffers or recesses (14) in the underside of the panel and reinforcing rods (22, 24) in the upper surface, in the ribs (20) defined by the recesses (14) and in lateral projections (12) from two opposed edges of the panel. The lateral projections (12) fit into hard rubber wedges which themselves engage side flanks of the rails of the railway or railroad.

Description

SPECIFICATION Rail crossing panel This invention relates two panels incorporated in railway level crossings.

Some years ago a novel and much improved design of level crossing structure was introduced into the United Kingdom and has been widely adopted by British Rail as the construction is relatively straightforward to instal and if correctly carried out gives a far smoother passage for road traffic.

Such level crossings comprise a number of components of which the largest and heaviest are the panels which are mounted above the sleepers of the rail track and extend between and are mounted on the side flanks of the rails. Other panels forming parts ofthe crossing assembly are also liable to be heavy enough to render weight saving desirable.

It will be understood that these panels are subject to heavy loadings, sometimes involving impact and it follows that substantial amounts of steel reinforcement have been included and furthermore an external frame of metal has been provided to add to the overall strength of the panel. Atypical panel of the kind in question may weigh 265 Kg or even more and this generally involves the use of mobile cranes with resultant increased cost, not only from the expense of hire or depreciation of the crane but because the crane can often present an impediment to otherwork being carried out on site.

With the objective of reducing the weight while retaining adequate strength for the onerous task involved it has been proposed to use polyester concrete which has a higher tensile strength for a given weight than conventional Portland cement based concrete and this has resulted in a reduction in weight, but not to a sufficient degree to enable easy manhandling ofthe panels on site. Atleasta partof the weight reduction has been made possible by omission of the external frame hitherto used. The remainder of the weight saving has been achieved in this relatively recent proposal by the use of polyester concrete and a slight reduction in thickness ofthe panel.

According to the present invention there is provided a concrete panel for incorporation in a rail level crossing structure, the panel comprising polyester concrete with recesses in the undersurface and appropriate reinforcement at least at or adjacent the top and bottom surfaces.

The invention will now be described, byway of example only, with reference to the accompanying diagrammatic drawing in which: Figure lisa pian view of a concrete panel in accordance with the present invention; Figure2 is a fragmentary section illustrating an edge portion ofthe panel of Figure 1 and in vertical section; and Figure 3 is a fragmentary view illustrating one feature of the present invention.

Referring now to the drawing, a concrete panel in accordance with the invention generally referenced 10 is rectangular in plan view but has four ears or lateral projections 12 by which opposed edges of the panel are supported by the opposed flanks ofthe rails of the associated railway trackthough the intermediary of hard rubberwedges(notshown).

Typical dimensions for use in conjunction with standard gauge track are given in the drawing and, as will be apparent, from Figure 1 and Figure3the underside has six recesses 14with the objective of reducing the overall weight of the panel.

The recesses on the undersurface are trapezoidal in both orthogonal sections and extend towards the upper surface so that at maximum depth the panel has a thickness of approximately one quarter the maximum depth at the ribs or lands 20, between the recesses.

As shown six recesses, or coffers are shown, but a greater or lesser number may be incorporated. It is not likely that less than fourwill be used.

The panels are so constructed that they follow, on the undersurface, the shape of a conventional prestressed concrete railway sleeper although there is no contact between the sleeper and the undersurface. Figure 3 illustrates this feature. As will be apparent from the fragmentary views of Figures 2 and 3 the edge portion of the panel is 120 mm thick whilst the central portion where the recesses are provided is 135 mm thick, and this provides an important advantage from the point of view of improved tensile strength by the inclusion of reinforcement rods at a lower level in reiation to the load receiving surfacethan would be possible if the undersurface were plane over its whole extent. The shape in this respect also ensures that the highest strength is available where the stresses are highest.

The need for greater depth, particularly at the central area of each panel results from the lower modulus or stiffness of polyester.

The ears or projections 12 are generally conventional and as shown in Figure 2 are provided on the undersurface with a recess 16 and on the upper surface with a chamfer 18, the recess and the chamfer being adapted generally to the cross-sectional shape of a wedge (not shown) engaged against the flank of a conventional rail.

It is conventional practice to incorporate in a level crossing a cattle grid which also serves to deter at least unauthorised persons from straying on to rail tracks. By the use of polyester concrete it becomes possible to make the sharply inwardly pointed grids of concrete in place oftimber.

Panels in accordance with the present invention are made of polyester concrete and required no external frame. Reinforcement is entirely internal and because of the higher impact resistance of polyester concrete the risk of chipping during installation or subsequent use at the edges is substantially eliminated. The polymer may be ofthe kind which is basically made of Portland cement and is impregnated after setting. The polymer may otherwise be added tithe mix of cementicious concrete prior to setting and a third possibility isto omit Portland cement entirely and rely solely on the polymer. Normally the polymer will be a polyester.

Polyester concrete gives rise to the additional advantagethattheelectrical resistance is higher than that of conventional concrete mixes and the omission ofthe external frame also gives rise to advantage of reduced riskofleakagecurrents.

Because of the electrical resistance advantage it is desirable that all panels of a crossing should be made of polyester concrete.

A standard internal panel for a level crossing as hereinbefore particularly described has been found to have a weight saving in relation to conventional panels of approximately 25%. This is sufficientto enable manhandling bythree orfour men without risk of back damage. Other panels of a crossing will also give a similarweightsaving.

Claims (9)

1. A concrete panel for incorporation in a rail level crossing structure, the panel comprising polyester concrete with recesses in the undersurface and reinforcement means at least at or adjacentthe top and bottom surfaces ofthe panel.

2. A panel according to claim 1 comprising four lateral projections at opposed edges of the panel by which the panel can be supported by the opposed flanks ofthe rails of the associated rail track.

3. A panel according to either claim 1 or claim 2 wherein the recesses on the undersurfaceofthe panel are trapezoidal in both orthogonal sections.

4. A panel according to any one of the preceding claims wherein the recesses extend towards the upper surface ofthe panel so that at maximum depth the panel has a thickness of approximately one quarterthe maximum depth of lands or ribs defined between the recesses.

5. A panel according to any one of the preceding claims comprising six said recesses.

6. A panel according to any one of the preceding claims wherein edge portions of the panel have a Iesserthicknessthan those portions ofthe panel where the recesses are provided, reinforcement rods being provided closerto the lower surface ofthose central portions defining the recesses.

7. Apanel accordingto any one of claims 2 to 6 wherein each ear or projection is provided on its undersurface with a recess and on its upper surface with a chamfer.

8. A concrete panel for incorporation in a rail level crossing structure substantially as hereinbefore described with reference to the accompanying drawings.

9. A railway level crossing structure incorporating panels in accordance with any one of the preceding claims.