EP0838552B1

EP0838552B1 - Points for a railway line

Info

Publication number: EP0838552B1
Application number: EP97919409A
Authority: EP
Inventors: José Antonio BARRENCUA LEON; Juan Carlos Sanchez Jorrin
Original assignee: JEZ Sistemas Ferroviarios SL
Current assignee: JEZ Sistemas Ferroviarios SL
Priority date: 1996-04-29
Filing date: 1997-04-24
Publication date: 2003-05-28
Anticipated expiration: 2017-04-24
Also published as: ES2137807B1; ES2137807A1; PT838552E; ES2208894T3; WO1997041305A1; EP0838552A1

Description

The object of this invention refers, as its title indicates, to an acute swing nose crossing for railways, which can be incorporated to a continuous welded-rail, comprising a fixed element and a movable element, presenting important advantages over the methods currently used for this purpose.

Currently, two main embodiment types of acute swing nose crossings are known, as described below.

The first known type of acute swing nose crossing includes those crossings carried out entirely assembled, where the housing or casing, that is, the fixed element, is made of rails, preferably joined by brackets and bolts and nuts to a plate assembly, in turn joined to the sleeper, and the movable element is made of machined carbon steel rails or forged elements of the same material. Likewise, with the purpose of improving the wear properties in the rolling areas, different heat hardening treatments have been proposed in said areas.

The second known type of acute swing nose crossing for railways groups those crossings in which the fixed element, in its front part, is a cast mono-block, preferably of austenitic manganese steel, and the moving element is entirely made of machined rails.

Nevertheless, in the crossings of the first type, disadvantages are presented derived from the use of a fixed element with bolted joints, such as the maintenance requirements during service as well as the high noise level produced in case of misadjustment or loosening of said joints. Likewise, even when improving the wear behavior of the steel by means of a known heat treatment, like pearlitizing or others, said procedure is generally performed both on the fixed element and the movable element exclusively in the areas nearest to the surface, so that said characteristic of improved hardness is lost as the wear or the in-depth maintenance grinding advance. Finally, the difficulty of repairing the defects in the rolling area by means of welding should be mentioned, due to, for example, skidding of the train wheels, impacts, denting of the ballast on the rolling table, etc. due to the wear or loss of the delicate heat treatment after repairing the affected area. Anyway, said repair by welding, would have to be performed with great perfection and by very qualified personnel, due to its great importance, difficult circumstances when works are made outdoors.

For all these reasons, the crossings of the second described type represent an improved design with respect to the crossings of the first type, on eliminating the assembled fixed element and replacing the latter by a cast mono-block housing, preferably of austenitic manganese steel and making the movable element of a machined rail. In this case, the bolted joints are eliminated in the fixed element area bearing the passage of the wheel, with the consequent saving in maintenance costs. Likewise, with the preferable construction in moulded austenitic manganese steel, the beneficial properties of said material with respect to impacts and wear are taken advantage of.

However, in crossings of said second type, the movable element is made by means of machined rails, with the aforementioned disadvantages involved in this type of execution.

In the railway field, the properties and advantages resulting from the use of austenitic manganese steel, due to the excellent combination of impact and wear resistance are well known. Said material undergoes a marked characteristic of surface hardening by means of cold deformation on the passage of train wheels, in such a way that at its surface, an extremely hard layer is formed which is suitable to resist wear and keep in its core a high ductility permitting it to resist impacts and crack propagation.

When implemented, said material has a moderate natural surface hardness (approximately 200 HBN), so that in the first moments working it undergoes plastic deformations due to the passage of train wheels, causing the typical lips and burrs on the edges of the rolling table. In fixed crossings, said phenomenon requires a maintenance work consisting of eliminating burrs by grinding when the crossing has achieved its superficial regime hardness (approximately 350 HBN-400 HBN).

Nevertheless, in swing nose crossings, a perfect coupling between the tongue or movable element and the housing of fixed element has to be assured to prevent the mismatching phenomena between both elements, which may damage the tongue when the train is passing or even cause its derailment, so that it is necessary to prevent burr phenomena in said coupling area.

With the purpose of efficiently rectifying the defects these currently existing swing nose crossings have, an acute swing nose crossing for railways has been developed, which is the object of this invention as defined in independent claims 1 and 5.

More specifically, this invention refers to an acute swing nose crossing suitable for being coupled to entrance and exit rails, consisting of a fixed element and another movable element, in which the former consists of a first part made of cast manganese steel and of a second part made in rails, preferably formed by joining two rails to said first part, which are appropriate to act as anchoring elements for accessories such as buffers, heel-blocks, ribbed plates and expansion joint and whose movable element consists of an element made of cast manganese steel and of two rail parts joined to the former, one of said rails being joined to said part made of rails of said fixed element by means of bolted heel-blocks and joining the other of said rails to the expansion joint, this latter part of the longitudinal rail sliding in the expansion joint on the side of the diverted line suitable to prevent the assembly formed by said moving element from forming a non-deformable triangle. Likewise, the acute swing nose crossing, object of this invention, has sliding means for the movable element inside the fixed element, as well as means for coupling the moving element to the right or to the left.

Said rail parts, both the fixed element and the moving element, which are joined to the respective parts made of moulded manganese steel, as well as the union of the fixed moulded part with the entrance rails, is made by means of a welding procedure, preferably by flash butt welding. Likewise, the union or unions of the moulded part of the moving element with the rail parts of said movable element are reinforced, preferably by means of safety fish plates.

Said cast parts, both of the movable and fixed elements can be made of heat treated carbon or low alloy steel, and joined to the adjacent rails, that is, both parts of both elements made in rail, and the entrance rails, by means of conventional welding procedures. In the preferred embodiment, said parts made of cast manganese steel are preferably hardened by explosive hardening in the areas subjected to wear and/or deformation by the train wheels, as well as in the areas of mutual coupling between said parts, up to a hardness of approximately 350 HBN.

From all the above, the advantages contributed by the acute swing nose crossing for railways, object of this invention, in its preferred embodiment can be easily deduced, in this way constituting an improvement over the two main existing types of swing nose crossing. Firstly should be mentioned the advantages contributed by using high manganese content austenitic steel in the rolling areas, on both the fixed and the movable elements, since it benefits from the advantages of said material itself, because it is a material that can easily be repaired by welding, is resistant to wear and impacts in the most critical crossing areas and the hard layer of the material is regenerated with the passage of the wheels, as compared with materials hardened by heat treatment, whose hard layer gradually disappears with wear. Likewise, the use of monolithic parts instead of assembled ones requires less maintenance and involves greater safety.

On the other hand, the explosive impact hardening of the manganese steel in the coupling areas of both the moving and fixed elements, as well as in the rolling areas, permits a longer lasting operation of said elements, since it previously acquires an elevated hardness preventing initial wear and plastic deformations occurring in non-hardened manganese steel elements, a better conservation of the ideal geometrical shape of the elements subjected to contact with the wheel, nose and housing, hence avoiding the formation of burrs, which may hinder the correct coupling between both, as well as noises and impacts in rolling and lower conservation costs, on preventing grinding jobs and burr elimination.

The described characteristics of the acute swing nose crossing for railways, object of this invention, make it suitable for use in high speed lines (speeds higher than 300 km/h), as well as on lines of heavy loads per axle (loads higher than 25 t per axle), the detail design being adapted to the specific requirements of these types of exploitation.

To understand the object of this invention better, a preferred practical embodiment of the acute swing nose crossing for railways is described below, on the basis of the attached figures. Said figures show:

Figure 1, shows a plant view of the acute swing nose crossing for railways, object of this invention, giving passage to the circulation by direct rail, considering that said crossing is integrated in a simple diversion, with diversion to the right.

Figure 2, shows a plant view of the acute swing nose crossing for railways represented in the previous figure, giving passage to the circulation along the diverted rail.

Figures 3, 4 and 5 represent the cross sections AB, CD and EF of figure 1, respectively.

Figure 6 shows a plant view of the part made of cast manganese steel of the fixed element of the acute swing nose crossing for railways, object of this invention.

Figure 7 shows the cross section OP of the part shown in the previous figure.

Figure 8 shows a plant view of the part made of cast manganese steel of the movable element of the acute swing nose crossing for railways, object of this invention.

Figures 9 and 10 show the cross sections QR and ST of the part shown in the previous figure, respectively.

As shown in figures 1 and 2, the acute swing nose crossing for railways, object of this invention, consists of a fixed element (1) and another movable element (2).

The fixed element (1) comprises a first moulded part (1A) made of cast manganese steel and a second part (1B), formed by joining two rails to said first molded part (1A), which are appropriate to act as anchoring elements for accessories such as buffers, heel-blocks, ribbed plates and expansion joint (3).

The movable element (2) consists of a first moulded part (2A) of a triangular shape made of cast manganese steel and of two rail parts (2B, 2B'), joined to said moulded part (2A) at its heel, by means of one or two of its extensions. One of said rail parts (2B) is joined to said part made of rails (1B) of said fixed element (1) by means of bolted heel-blocks (4A, 4B, 4C). The other of said rail parts (2B') of the movable element (2) slides longitudinally on the expansion joint (3) formed by the rail part (2B') and the splice rail (5), with the purpose of preventing the triangle formed by said movable element (2) joined to the heel-blocks (4A, 4B, 4C) comprising a non-deformable triangle on making its lateral movement. Said parts of rail (2B, 2B') of the movable element (2) may be joined to the moulded part (2A) by means of two independent joints, as shown in figures 1 and 2 or by means of a single double joint of both parts of the rail (2B, 2B') with said moulded part (2A).

Figures 1 and 2 show the movable element (2) coupled on the fixed element (1), opening the way to circulation along the direct line and the diverted line, respectively. In both figures, the transfer of rolling between the fixed element (1) and the movable element (2) is performed in the respective parts made of moulded manganese steel (1A, 2A), taking advantage of the excellent impact and wear characteristics of said material, since in this area impact and wear loads are produced, especially when worn double flanged wheel sets circulate.

In this way, the moulded part (1A) of the fixed element (1) consists of an extended and hollow housing, the moulded part (2A) of the movable element (2) slides inside said part (1a) (see figures 3 and 4), being joined on one side to the entrance rails (6) by means of a flash butt welding procedure and, on the other, to the part made of rails (1B) of the fixed element itself (1), the latter being a support part of other items, such as buffers, heel-blocks, etc.

Since the acute swing nose crossing object of this invention, can be incorporated to continuous welded lines, the rail part (2B') and the splice rail (5) are directly welded to the adjacent rails by means of a procedure such as thermit welding. Since the manganese steel making up the moulded part (1A) of the fixed element (1) and the carbon steel of the adjacent rails (6) cannot be welded in a conventional way, it is necessary to use a special welding procedure, preferably by flash butt welding, for the union of the former.

Said special welding procedure, preferably by flash butt welding will also be used for the joint or joints (7) of the moulded part (2A) with the rail parts (2B, 2B') of the movable element (2).

As said joint or joints (7) are subjected to reversed bending when making the switch operation of the movable element (2), said joints are reinforced by means of safety fish plates (8) bolted to the web of the parts of the movable element (2), to provide greater safety to said joint before said stresses.

Figures 3, 4 and 5 show different cross sections of the swing nose crossing for railways represented in figure 1. More specifically, figure 3 (section AB) corresponds to a coupling section of the moulded manganese steel parts (1A, 2A) in the position of the movable element (2) shown in figure 1. Of course, the other position of the movable element (2) will be symmetrical to that shown in said figure 3. Figure 4 (section CD) corresponds to a section in the area where there is no direct coupling between the fixed element (1) and the movable element (2). Finally, figure 5 (section EF) corresponds to a crossing section representing the embedded area between the fixed element (1) and the movable element (2).

The moulded parts (1A, 2A) made of cast manganese steel are preferably hardened by explosive hardening in the areas subjected to wear and/or deformation by the train wheels, as well as in the areas of mutual coupling between said parts, up to a hardness of at least 350 HBN approximately. Figures 6 and 7 show by means of a grid and a dotted dashed line, respectively, different views of the areas to be hardened by explosive hardening of the moulded part (1A) of the fixed element (1) corresponding to the rolling table and the coupling area between the former and the moulded part (2A) of the movable element (2). Likewise, figures 8, 9 and 10 show by means of a grid and a dotted dashed line, respectively, different views of the areas to be hardened by explosive hardening of the moulded part (2A) of the movable element (2) coincident with the rolling table and with the coupling area between the former and the moulded part (1A) of the fixed element (1).

The acute swing nose crossing is completed with devices such as locks, detecting rods, as well as other parts, which are not object of this patent.

The entire assembly of the invention will be adjusted to the different cants the rolling elements may take, whether 1:20, 1:30, 1:40 and even 1:∞.

Once the nature of this invention as well as a way to execute it have been sufficiently described, it should only be added that as a whole and in its parts, it is possible to introduce changes of shape, materials and arrangement, provided that said alterations do not substantially vary the characteristics of the invention claimed below.

Claims

An acute swing nose crossing for railways, wich can be incorporated into a continuous welded rail, comprising a fixed element and a movable element, characterized in that the fixed element (1) consists of a first moulded part (1A) made of cast manganese steel and of a second part made of rails (1 B), formed preferably by the union of two rails to said first moulded part (1A), which are appropriate to act as anchoring elements for accessories such as buffer, hell-block, ribbed plates and expansion joint (3), in that the movable element (2) consists of a moulded part (2A) made of cast manganese steel and of two rail parts (2B, 2B') joined to the former, one of said rail parts (2B) being coupled to said rail parts (1 B) of said fixed element (1) by means of bolted heel blocks (4A, 4B, 4C), and joining the other of said rail parts (2B') to the expansion joint (3), and in that it provides means for sliding said movable element (2) inside said fixed element (1), as well as means for coupling the movable element (2) to the right or to the left.
An acute swing nose crossing for railways, according to the previous claim, characterized in that said rail part (2B') of the movable element (2) slides longitudinally in said expansion joint (3) on the side of the diverted line, suitable to prevent the triangle formed by said movable element (2) from constituting a non-deformable triangle.
An acute swing nose crossing for railways according to the previous claims, characterized in that the union of said rail parts (1B, 2B, 2B'), both of the fixed element (1) and the movable element (2) to the respective moulded parts (1A, 2A) made of moulded manganese steel, as well as the union of said moulded part (1A) of the fixed element (1) to the entrance rails (6), is made by means of a welding procedure, preferably flash butt welding and in that the joint or joints (7) of the moulded part (2A) with the rail parts (2B, 2B') of the movable element (2) are reinforced by means of safety fish plates (8).
An acute swing nose crossing for railways, according to claims 1, 2 and 3, characterized in that the moulded parts (1A, 2A) made of cast manganese steel, are hardened by explosive hardening to an approximate hardness of 350 HBN in the areas submitted to wear, deformation by the train wheels, as well as areas of mutual coupling between them.
An acute swing nose crossing for railways, which can be incorporated into a continuous welded rail, comprising a fixed element and a movable element, characterized in that the fixed element (1) consists of a first moulded part (1A) made of carbon or low alloy steel and of a second part made of rails (1 B), formed preferably by the union of two rails to said first moulded part (1A), which are appropriate to act as anchoring elements for accessories such as buffers, heel- block, ribbed plates and expansion joint (3), in that the movable element (2) consists of a moulded part (2A) made of carbon or low alloy steel and of two rail parts (2B, 2B') joined to the former, one of said rail parts (2B) being coupled to said rail parts (1B) of said fixed element (1) by means of bolted heel blocks (4A, 4B, 4C), and joining the other of said rail parts (2B') to the expansion joint (3), in that it provides means for sliding said movable element (2) inside said fixed element (1), as well as means for coupling the movable element (2) to the right or to the left, and in that the rolling surfaces of the moulded parts (1A, 2A) are heat treated and said moulded parts (1A, 2A) are joined to the rail parts (1B, 2B, 2B') and adjacent rails (6) by means of conventional or special welding procedures.
An acute swing nose crossing for railways, according to claim 5, characterized in that said rail part (2B') of the movable element (2) slides longitudinally in said expansion joint (3) on the side of the diverted line, suitable to prevent the triangle formed by said movable element (2) from constituting a non-deformable triangle.
An acute swing nose crossing for railways according to claims 5 and 6, characterized in that the union of said rail parts (1B, 2B, 2B'). both of the fixed element (1) and the movable element (2) to the respective moulded parts (1A, 2A) made of carbon or low alloy steel, as well as the union of said moulded part (1A) of the fixed element (1) to the entrance rails (6), is made by means of conventional or special welding procedures and in that the joint or joints(7) of the moulded part (2A) with the rail parts (2B, 2B') of the movable element (2) are reinforced by means of safety fish plates (8).
An acute swing nose crossing for railways, according to the previous claims, characterized in that the rolling elements, both fixed and movable, take cants preferably of 1:20, 1:30, 1:40 or 1:00.