GB1590288A

GB1590288A - Rail crossings

Info

Publication number: GB1590288A
Application number: GB5276877A
Authority: GB
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG
Priority date: 1976-12-23
Filing date: 1977-12-19
Publication date: 1981-05-28
Also published as: BE862219A; FR2375391A1; DE2752708B2; AT346884B; DE2752708A1; ATA963476A; BR7708589A; DE2752708C3; JPS5383212A; PL203196A1

Description

(54) RAIL CROSSINGS (71) We, VEREINIGTE OESTERREICH ISCHE EISEN- UND SrAHLwERKE-ALPINE MONTAN AKTIENGESELLSCHAFT, an Austrian Company of A-1011 Vienna, Friedrichstrasse 4, Austria, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly des cribed in and by the following statement: Frogs for use in rail switches and rail crossings are subjected to high stresses owing to the high speeds of travel and the steadily increasing density of traffic. Such frogs con sisting of austenitic manganese steel castings have proved particularly satisfactory.Whereas a good joint between the frog and the adjoining track rails is essential and welded joints are preferable, great difficulties are involved in the welding of such castings of austenitic manganese steel and the track rails. The joint is heated during the welding operation and austenitic manganese steel must be cooled quickly so that its structure is austenitic as far as possible. On the other hand, the low-alloy rail steel must be cooled slowly in order to prevent a formation of martensite and Ibainite. These mutually in cosistent requirements give rise to great problems. It has already been attempted to weld with a controlled supply of heat, e.g.

in manual electrode welding. It has also been attempted to minimize the heat supply; this appears to be enabled by the use of laser rays or by electron beam welding.

Whereas in these methods the ends to be welded together are 'heated only in a smaller region, the parts are still heated to some extent so that the problem which is due to the mutually inconsisting cooling require ments remains. Such welding operations can not be performed on the site. It has also been attempted to join a metallurgically suitable connector by flash butt welding to the casting of austenitic manganese steel and to provide such connector with a hard facing by weld surfacing because the connector as such does not withstand the stresses which are due to the travel. The connector may be made from a material which is not damaged by the rapid cooling of the welded joint between the connector and the frog consisting of a casting of austenitic manganese steel.

The welded joint for connection to the track rail does not give rise to problems in that case because the hard-faced connector may be cooled slowly. On the other hand, disadvantages which remain reside in that the weld surfacing required to provide the hard facing results in a heating also of the casting of austenitic manganese steel at the wheelengaging surface, which is subjected to the highest stresses, so that the difficulties involved in the cooling arise again, and that the process is complicated and expensive because a hard facing is required. When it was desired to utilize the advantages of austenitic manganese steel castings with respect to the wear resistance of the frog, it was necessary, for this reason, to provide a conventional fishplate joint and such conventional strapped rail joints are usually employed between frogs and track rails.

Such fishplate joints do not prevent a strong squeezing of the ends of the track rails at the frog ends and are not reliable in operation, so that the conventional fishplate joints must be checked continually and must often be repaired.

It is known, for example from British Patent specification No. 848,143 (Brevets lndustriels) and United States Patent specification No. 3,952,948 (Nelson) to provide a joint between track rails in which fishplates are clamped and adhesively bonded to the ends of the track rails. The present invention is based upon a realisation that by adopting a similar solution, the quite different problem of joining a cast austenitic manganese steel frog can be solved in a satisfactory manner.

The invention provides a frog which conmists of an austenitic manganese steel casting and is intended for use in a rail switch or rail crossing, adjoining by rail ends and at its rail-adjoining ends having the same profile in the rail head and the rail web at least on one side of the axis of symmetry as the adjoining rail ends, characterised in that the rail-adjoining ends are connected to the adjoining rail ends using fishplates which are clamped in position by screws and the adjoining rail ends consist preferably of the ends of the track rails. Because the adjoining rail ends are joined to the rail-adjoining ends of the frog using fishplates which are adhesively bonded and are clamped in position using screws, the resulting joint between the frog and the adjoining rail ends is rigid and will resist all stresses which are due to the travel.Above all, any thermal stress on the frog consisting of an austenitic manganese steel casting is avoided. If the adjoining rail ends consist of the ends of the track rails, the joint must be made on the site in the track. Because the adhesively bonded fishplates are also clamped by screws, a durable adhesive bond can be obtained within shorter intervals of time between trains because the screwed joint takes up the forces which are due to slowly moving trains, even when the synthetic resin has not yet been completely cured. As a result, a reliable joint is ensured when the adhesive bonds have been carefully made. Alternatively, the adjoining rail ends may consist of connectors made of highly wear-resisting rail steel and adapted to be welded to the track rails at the ends remote from the frog.

In that case the adhesive and screwed joints can be made in the factory in dust-free rooms at suitable temperatures. Whereas this practice may afford certain advantages, the track rails must be welded to the connectors on the site. Such connectors afford the advantage that they constitute a heat buffer, which prevents a heating of the frog consisting of an austenitic manganese steel casting. A detrimental temperature rise of the adhesive bond during the welding operation will be avoided if such connectors have a sufficiently large length, e.g. of about 25 cm.

In almost all cases the rail-adjoining ends of the frogs diverge at a very acute angle, which does not exceed 30 . In such cases the space between the rail-adjoining ends of the frog is very narrow. In accordance with a preferred embodiment of the invention the arrangement is such in these cases that the fishplates between two divergent rail-adjoining ends have tapped bores and the connecting screws are headed and extend through threadless bores of the outer fishplates and of the rail webs and are screwed into said tapped bores. In that case the rail-adjoining end portions of the frog may be short because the nuts usually emp]oyed in fiishplate joints can be omitted. This decreases the length of the frog, which is otherwise long when the rail-adioining ends include such an acute angle.Shorter frogs have the advantage that the danker of distortion is reduced and that the frogs can be manufactured and transported more easily, particularly in view of the fact that the length of the heating furnaces which are available is limited. The space between the divergent rail-adjoining ends of the frogs and between the adjoining rails increases with the distance from the body of the frog. If the space between the rails ends to be joined is sufficiently large, a fishplate joint comprising bolts and nuts can be used there so that the taped bores in the inner fishplates may be required only adjacent to the rail-adjoining ends of the frog.

In another preferred embodiment of the invention, the fishplates disposed between the divergent rail-adjoining ends constitute a common body, which is integral with the frog and extends beyond the rail ends which are to be joined. This design affords the advantage that the common body which is integral with the frog and constitutes the inner fishplates results in a higher strength of the joint between the frog and the adjoining rail ends.

In a preferred embodiment, the diameter of the bores in the outer fishplates and in the rail web exceeds the crest diameter of the screw threads of the connecting screws, and the annular clearance between the connecting screws and the bores and the gaps between the abutting end faces of the railadjoining ends and the adjoining rail ends are filled with the synthetic resin which is used as a adhesive. In that case the plastics material used as an adhesive insulates the frog from the adjoining rail ends so that the rails may be used to transmit electrical signals.

In accordance with the invention the connecting screws are suitably coated with a parting agent, which prevents a bonding of the screw to the plastics material which fills the bore. This affords the advantage that the connecting screws can be re-tightened when the adhesive has set.

Illustrative embodiments of the invention are diagrammatically shown on the drawing, which illustrates the connection of track rails to the frog.

Fig. 1 is a top plan view showing a frog, Fi. 2 a sectional view taken on line lI-lI in Fie. 1, Fig. 3 is a sectional view taken on line Ill-Ill in Fig. 1. Figs. 4, 5 and 6 show another embodiment. Fig. 4 is ain a top plan view showing the frog and the adjoining track rails, Fiv. 5 is a sectional view taken on line V-V. Fig. 6 a sectional view on line VI-VI. Fi. 7 a sectional view taken on line VIl-VIl and Fi. 8 a sectional view taken on line VIII--VIII in Fig.

4.

In the embodiment shown in Fig. 1, a frog 1 has rail-adioining ends 2 and 3, which adioin track rails 4 and 5. The rail-adioining end 2 and 3 of the frog 1 have the same profile as the track rails in the head and web. The track rails 4 and 5 are connected to the rail-adjoining ends 2 and 3 of the frog 1 by fishplates 6 and 7. The fishplates 7 are the inner fishplates disposed between the rail-adjoining ends 2 and 3. The fishplates are adhesively bonded by means of synthetic resin, e.g. by means of a cast resin which contains a filler, for instance, by means of an epoxy resin which contains quartz powder.

When the cast resin has cured, its ball indentation hardness should be 1500 kg/cm2, preferably at least 2000 kg/cm2. The compressive strength should be 1200 kg/cm2, preferably at least 1800 kg/cm2. It is believed that a polyurethane plastics material can be used instead of the epoxy resin.

The fishplates 6 and 7 are clamped toward each other by connecting screws 10. The fishplates 7 are provided with tapped bores 11 so that they constitute nuts. This affords the advantage that it is not necessary to introduce nuts into the narrow space 12 between the two rail-adjoining ends 2 and 3 so that the joint may be nearer to the center of the frog 1 and the latter may be shorter.

Layers 8 and 9 made of plastics material are provided between each of the fishplates 6 and 7, on the one hand, and the adjacent rail-adjoining end 2 or 3 and the adjacent track rail 4 or 5, on the other hand. The bores 13 in the fishplates 6 and the bores 14 in the webs of the track rails 4 and 5 and of the rail-adjoining ends 2 and 3 are larger in diameter than the shafts of the connecting screws 10. The synthetic resin which is used as an adhesive is also disposed in the clearances which are left in the bores 13 and 14.

These clearances may also contain bushings of insulating material. The heads of the screws 10 engage washers 15 made of insulating material. A layer of the synthetic resin which is used as an adhesive is provided also in the gaps 16 between the abutting end faces of the rail-adjoining ends 2, 3 and the track rails 4, 5. This results in an electrical insulation between the frog 1 and the track rails 4 and 5.

The embodiment shown in Figs. 4 to 8 differs from the embodiment shown in Figs.

1 to 3 in that the two inner fishplates 7 at each end of the frog are combined in a common body 17 or 21, which is integral with the frog 18. Each of the screws 10 extends through one of these common bodies 17 and 21 and is fixed by a nut 19. The adhesive bonds are provided as in the arrangement shown in Fig. 1. Adhesive layers 8 and 9 are again formed and the screws 10 are insulated from the track rails 4 and 5 just as in the embodiment shown in Figs. 1 to 3. The gaps 16 between the abutting end faces are also filled with synthetic resin. In this way, an electrical insulation is also provided. In the rail web, the railadjoining ends 2 and 3 have the same profile as the track rails 4 and 5 only on the outside. On the inside, the rail web merges into the body 17 and is integral with the latter.

This design results in a much stiffer joint.

In the sectional view shown in Fig. 6 it is seen that the two rail-adjoining ends 2 and 3 are separated by a groove 22, which is adapted to receive the wheel flange, which is disposed on the inside in that region. In the sectional view of Fig. 7, the two railadjoining ends are combined in a common body and are not separated by a groove for the wheel flange because the latter is disposed on the outside in that region. At both ends of the frog, the parts 17 and 21 protrude beyond the rail joints and constitute inner fishplates for connection to the adjoining track rails 4, 5. These inner fishplates are integral with the frog. The outer straps are designed as usual and are screw-connected to the rail-adjoining ends 2, 3 and the ends of the track rails 4, 5.

The track rails 4, 5 are preferably insulated from the frog. This may be accomplished in that the joints between the track rail 4, 5 on the one hand, and the part 17 and the fishplates 6, on the other hand, are insulated and the track rails and the fishplates 6 are insulated from the screws 10, as is shown in Figs. 5 and 6. Figs. 7 and 8 show that the screws 10 are insulated by bushings 20 from the rail-adjoining ends 2, 3 and from the part 21, although this is not necessarily required.

WHAT WE CLAIM IS:- 1. A frog which consists of an austenitic manganese steel casting and is intended for use in a rail switch or rail crossing, adjoined by rail ends and at its rail-adjoining ends having the same profile in the rail head and the rail web at least on one side of the axis of symmetry as the adjoining rail ends, characterized in that the rail-adjoining ends are connected to the adjoining rail ends using fishplates, which are adhesively bonded by means of plastics material and are clamped in position by screws and the adjoining rail ends consist preferably of the ends of the track rails.

2. A frog according to claim 1, which has rail-adjoining ends which diverge at an acute angle, particularly an angle up to 30 , and is adjoined by rail ends, characterized in that the fishplates between two divergent rail-adjoining ends have tapped bores and the connecting screws are headed and extend through threadless bores of the outer fishplates and of the rail webs and are screwed into said tapped bores.

3. A frog according to claim 1 or 2, which is adjoined by rail ends, characterized in that the diameter of the bores in the outer fishplates and in the rail ends exceeds the crest diameter of the screw threads of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. to the rail-adjoining ends 2 and 3 of the frog 1 by fishplates 6 and 7. The fishplates 7 are the inner fishplates disposed between the rail-adjoining ends 2 and 3. The fishplates are adhesively bonded by means of synthetic resin, e.g. by means of a cast resin which contains a filler, for instance, by means of an epoxy resin which contains quartz powder. When the cast resin has cured, its ball indentation hardness should be 1500 kg/cm2, preferably at least 2000 kg/cm2. The compressive strength should be 1200 kg/cm2, preferably at least 1800 kg/cm2. It is believed that a polyurethane plastics material can be used instead of the epoxy resin. The fishplates 6 and 7 are clamped toward each other by connecting screws 10. The fishplates 7 are provided with tapped bores 11 so that they constitute nuts. This affords the advantage that it is not necessary to introduce nuts into the narrow space 12 between the two rail-adjoining ends 2 and 3 so that the joint may be nearer to the center of the frog 1 and the latter may be shorter. Layers 8 and 9 made of plastics material are provided between each of the fishplates 6 and 7, on the one hand, and the adjacent rail-adjoining end 2 or 3 and the adjacent track rail 4 or 5, on the other hand. The bores 13 in the fishplates 6 and the bores 14 in the webs of the track rails 4 and 5 and of the rail-adjoining ends 2 and 3 are larger in diameter than the shafts of the connecting screws 10. The synthetic resin which is used as an adhesive is also disposed in the clearances which are left in the bores 13 and 14. These clearances may also contain bushings of insulating material. The heads of the screws 10 engage washers 15 made of insulating material. A layer of the synthetic resin which is used as an adhesive is provided also in the gaps 16 between the abutting end faces of the rail-adjoining ends 2, 3 and the track rails 4, 5. This results in an electrical insulation between the frog 1 and the track rails 4 and 5. The embodiment shown in Figs. 4 to 8 differs from the embodiment shown in Figs.

This design results in a much stiffer joint.

connecting screws and the annular clearances between the connecting screws and bores and the gaps between the abutting end faces of the rail-adjoining ends and the adjoining rail ends are filled with the synthetic resin which is used as an adhesive.

4. A frog or crossing part according to clairn 1, 2 or 3, which is adjoined by rail end portions, characterized in that the connecting screws are coated with a parting agent.

5. A frog according to any of claims 1 to 4, which has rail-adjoining ends which diverge at an acute angle, particularly an angle up to 30 , characterized in that the fishptates disposed between the divergent rail-adjoining ends constitute a common body, which is integral with the frog and extends beyond the adjoining rail ends.

6. A frog according to any of claims 1 to 5, which is adjoined by rail ends, characterized in that the adjoining rail ends consist of connectors made of highly wearresisting rail steel and adapted to be welded to the track rails at the ends remote from the frog.

7. A frog connected to adjoining rail ends using fishplates adhesively bonded to the frog and rail ends substantially as herein described.