US3139364A - Method of making railway track - Google Patents

Description

June 30, 1 R. A. FIECHTER METHOD OF MAKING RAILWAY TRACK 3 Sheets-Sheet 1 Filed Nov. 3, 1958 Iuvmnon M a. Hizdd'm b M 7 M AT'I'ORNLYS J1me 1964 R. A. FIECHTER METHOD OF MAKING RAILWAY TRACK 5 Sheets-Sheet 2 Filed Nov. 3, 1958 I A i A, PM.

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r W ATTORNEYS u 1964 R. A. FIECHTER METHOD OF MAKING RAILWAY TRACK 3 Sheets-Sheet 5 Filed Nov. 3, 1958 FIG-1O lNveNToR m QJ JWM y 93mm MW Answers United States Patent 3,139,36 RWTHUD 0F MAKDJ G RAKLWAY TRACK Rene A. Eiechter, Douglaston, N.Y., assignor, by mesne assignments, to American Railroad Curvelining Corporation, Douglaston, N.Y., a corporation of New York Filed Nov. 3, 1953, Ser. No. 771,378

2. Claims. ((21. 156-166) This invention relates to railway track construction and method of making same.

This application is a continuation-in-part of my prior application filed May 27, 1957, for Railway Rail Joint and Method of Forming It, under Serial No. 661,921, now Patent No. 3,100,080.

A conventional railway track comprises an assortment of elements, by which the rails are supported and located and by which the sections of rail are interconnected, such as ties, tie-plates or chairs, anti-creep devices and fishplates, the various elements, including the rails themselves, being held together by bolts, screw-spikes, spikes and the like.

The joints between mutually adjoining elements of such a conventional construction are not integra and, under the varying loads imposed by the trafiic, work, i.e., the joined elements suffer small, repeated, alternate relative displacements giving rise to wear and fatigue, which is additional to the inevitable wear and fatiguing of the rails themselves caused by the friction and hammering to which they are subjected by the traflic. Since the joints are not sealed, wear of the joint surfaces is aggravated by the penetration between them of hard particles, mostly derived from the ballast, and by oxidationand other atmospheric corrosion-products. Fish-plated rail-joints are recognized as especially weak points of the structure, the depression of the trailing rail-section of the joint causing dislocation of the joint itself and consequent wear of the mutually abutting rail ends when in contact. Moreover, thermal expansion and contraction of the rails impose alternating stresses on the fish-plates and fish-plate bolts. The above-mentioned disadvantages of fish-plated railjoints, as well as the noise nuisance caused by the passage of the train wheels over the rail-joints, as well as actual damage caused by the transmission through the rail of longitudinal and transverse vibrations of sonic or ultrasonic frequency, have to some extent been overcome by welding the rail-joints to produce continuous lengths of welded-up rail, whereby, inter alia, the thermal stresses are confined to the rail itself; but a welded rail-joint can only be parted, eg for replacing an excessively worn section of rail, by a cutting operation.

An object of my invention is to overcome the disadvantages of the conventional constructional methods, including the use of continuous lengths of welded-up rail.

Another object of my invention is to provide a method of constructing railway-tracks including, among the usual installing operations, the step of interposing between the otherwise contacting surfaces or fishing surfaces of the various elements of the railway track structure, a material which may form a bond between the joined elements, and when in place will preferably fill all the interstices of the joint and provide material continuity between the joined elements, sealing the joint against ingress of foreign bodies, such as abrasive particles and moisture and protecting the joint faces against atmospheric and other corrosion; the material in question having, in its final state, mechanical properties, in some respects at least, comparable with those of the joined elements and being substantially inert to corrosive influences.

A further object of my invention is the filling of the joints with an appropriate material, which not only protects the metal or other joint faces from corrosive influences and prevents the entry of foreign matter of an 3,139,364 Patented June 30, 1964 "ice abrasive or bruising nature, but also acts as it were a cushion, the elasticity of which may be adjusted, according to the requirements of any particular joint, by proper selection of the resin or resins constituting the filling material.

Yet another object of my invention is to use, for the purpose set forth, filling materials which have, incidentally, the property of forming a relatively strong bond with metal, or/ and with wood or concrete.

A further object of my invention is to permit eliminating conventional securing elements, such as bolts, screwspikes and spikes from the structure, at least in its final state.

Still another object of my invention is the complete filling of joints, or at least of the fishing surfaces, between mutually adjoining elements of a railway track or parts thereof, such as abutting rail ends, rails and fishplates, rails and tie plates, raids and anti-creep devices, tieplates and ties, with a filling material of a class which, when freshly prepared, is liquid or plastic, and in this state is sufficiently mobile to fill the interstices of the joint surfaces leaving practically no voids, but which has curing properties, will solidify on curing, will not contract ap preciably in curing, and when hardened will have compressive and shear strengths comparable with those of the joined elements, but a considerably lower tensile strength, the said material being applied in the as prepared state to the joint surfaces and caused to fill the interstices of the joint and then being cured.

In practice, the application of the above-defined method has been found to give unexpectedly successful results, in respect, inter alia, of mechanical strength and rigidity of the structure, reduced incidence of wear and fatigue and reduced inspection and maintenance; while owing to the relatively lower tensile strength of the filling material, the bonded elements can easily be parted by prying them apart, thus facilitating replacement of worn or damaged elements.

For carrying out the above-defined method, various materials having the required characteristics are available. Among them are magnesium cements, and cements having a complex thorium-oxysulphochloride base;

It is however a particular object of my invention to use certain thermosetting synthetic resins, with or without fillers, of the type including an epoxy-group (also known as ethoxyline resins), and more especially reaction products of epichlorohydrin such as are commercially marketed by the company called Ciba S.A. under the trademark or brand name Araldite I, and Araldite 123-13, the latter being mixed with a curing agent marketed by the said Ciba S.A. under the trademarks or brand names Hardener (Durcisseur) 953N.

The above-mentioned ethoxyline resins, in some cases with the addition of an appropriate curing agent, have self-curing properties at ordinary air temperatures, but the curing time is relatively long (e.g., 36 to 48 hours). Under moderate heating, however, to a temperature of, say, to C., the curing time is reduced to a few minutes.

When materials, such as ethoxyline resins, characterized by accelerated curing under heat, are used, it is a more particular object of my invention to provide a method as set forth above, including the step of heating the elements to be joined, after filling the joint with the filling material, to a temperature sufiicient to bring about rapid hardening of the filling material.

Still another object of my invention is to produce an interference fit between two elements to be joined, one male and the other female, by differential heating of the elements and forcibly pressing them together, the female element being raised to a higher temperature than the male element, said higher temperature however not being high enough to cause premature curing of the filling material,

3 and both elements being subsequently raised, while maintaining the pressure, to the accelerated curing temperature, the consequent differential expansion of the elements bringing about the interference fit.

A further object of my invention is to use the abovedefined filling material for mutually joining electrically conducting elements by an electrically conducting joint, whose conductive as well as its mechanical properties can subsist, without substantial deterioration and in the substantial absence of supervision and servicing, over pro longed periods.

Another object of my invention is therefore according to this further aspect of my invention, to provide a method of making an electrically conducting joint between conducting elements of a railway track assembly comprising the steps of roughening the joint surfaces, filling the joint with filling material of the class hereinbefore broadly defined, pressing the joint surfaces together with suflicient force to ensure that the high spots of each surface make effective contact with the other surface and that the current paths provided by said high spots are completely embedd in the filling material, the process being otherwise carried out as hereinbefore set forth, and the pressure being maintained until curing of the filling material is complete.

In a joint so made the conductive paths are completely protected against atmospheric corrosion and detrimental effects resulting from the penetration of foreign bodies, by the material in which they are embedded and which is substantially inert to chemical attack.

In a somewhat similar way, non-conducting joints be tween conducting elements can be elfected by introducing into the joint an electrically insulating member adapted to prevent any metal to metal contact of the joint faces, said insulating member being embedded in the filling material, said material being itself an electrical insulator.

An important application of my invention is in the making of a continuous length of rail from rail sections of conventional length by treating the joints between the abutting ends of the rail sections by the methods hereinbefore described.

From the point of view of strength, rigidity and distribution of thermal stresses, a continuous length of rail so formed is substantially equivalent to a welded-up continuous rail; and it has the advantage that owing to the relatively low tensile strength of the filling material, the joints can easily be parted for replacement purposes.

In addition, the transmission of vibrations along the rail is strongly damped without reflection at the joints, thus reducing the likelihood of generating stationary waves and their deleterious consequences in the way of giving rise to cracks in the rail, and hindering the tie-plates from vibrating on the ties.

Continuity of metallic rolling surface over the rail joints can be ensured by means of metal cover strips placed over the joints and rabbeted into the rail ends, the joints between such cover strips and the rail ends being completely filled with filling material by the methods hereinbefore described.

In a similar way, a whole length of rail may be clad with a continuous cover strip of metal having superior resistance to wear and punishment to that of the rail, as may be desirable in places, e.g., on curves, where the rail is subject to exceptionally heavy duty.

Irrespective of whether the joint-filling material has the property of forming an intimate bond with the substances (metal, wood or concrete) of the joined elements, its shear strength is of importance, since the material interengages with the macroscopic or microscopic roughness of the joint surfaces and can therefore transmit or sustain shearing stresses.

If a filling material having bonding properties is used and it is desired to take advantage of these properties by omitting conventional securing or clamping means, eg

mechanical continuity,

bolts, screw-spikes or spikes, it may nevertheless be necessary to use such securing or clamping means as a temporary meaure during the application and curing of the filling and bonding material, in which case the securing or clamping means may be pre-treated with a non-sticking agent, such as a silicone, enabling them to be extracted or removed without difficulty after the filling and bonding material has been cured.

In addition to the methods hereinbefore described, my invention also includes the products of such methods, namely railway tracks and parts thereof and continuous lengths of rail produced by said methods.

The nature of the invention Will be better understood from the following description, having reference to the accompanying drawings and given by way of example only, of typical rail track assemblies made by the methods of the invention. The scope of the invention is defined in the hereto appended claims.

In the drawings:

FIGURE 1 is a perspective view of a portion of railway track including two abutting rail sections, their supporting means and the joint between them;

FIGURE 1a is a section on the line aa of FIGURE 1 FIGURE 2 is a schematic section of a conducting joint between two electrically conducting elements;

FIGURE 3 is a fragmentary section on an enlarged scale of part of the Zone of contact of the elements of FIGURE 2;

FIGURE 4 is a view similar to FIGURE 2 of a nonconducting joint between two conducting elements, but in which mechanical continuity is obtained;

FIGURES 5 and 5a are fragmentary schematic sections of a rail foot and creep stop, FIGURE 5 illustrating the initial emplacement of the latter, and FIGURE 5a its final position;

FIGURE 5b is a section on the line 12-47 of FIGURE 5;

FIGURE 6 is a perspective view of a rail-joint effected, in a different manner, by means of a coupling sleeve;

FIGURE 7 is a transverse section of the rail-joint of FIGURE 6;

FIGURES 8 and 9 are views similar to FIGURE 7, illustrating modified forms of coupling sleeve;

FIGURE 10 is an elevation of two abutting rail sections, showing their supporting means and the joint between them, carried out in somewhat different manner than shown in FIGURE 1;

FIGURE 11 is a section on the line XI-XI of FIG- URE 10, parts being broken away.

Referring to FIGURE 1, two abutting sections of rail 1 and 2 are joined by a fish-plate 3 and the joint is covered by a cover strip 4 of metal, to receive which the rail heads are rabbeted to provide a flush rolling surface. The rails are supported on tie-plates 8, 15 laid on the ties 6, and are provided with anticreep devices 10, 11, I3, 14.

The structure illustrated in the left-hand half of the figure, i.e., the supporting of rail section 1, and its attachment to fish-plate 3, is conventional. Thus, the tie plate 8 is fastened to the tie 6 by conventional screwspikes 9 (one only being shown) and the rail foot is secured to the tie by a conventional spike 7; and the railsection 1 is attached to the fish-plate 3 conventionally, by bolts 12. The spikes 7 are preferably not driven fully home, allowing a play of say 10 mm, enabling the base of the rail to lift slightly from the tie-plate 8, assuming that the joint between the tie-plate and the base of the rail is not filled with the filling material above-mentioned.

Sideways shifting of the rail on the tie-plate is prevented by the shoulders 27 of the tie-plate which engage the edges of the rail foot (also see FIGS. 10, 11, below, in which the play between the spikes 107 and the railbase, and the shoulders 114, 115 are clearly shown).

On the other hand, the structure illustrated in the righthand half of the FIG. 1, i.e., the supporting of rail-section 2 and its attachment to the fish-plate 3, utilises the method of this invention to achieve the required mutual fixation of the several elements of the structure in an unconventional way. It will be seen that some of the conventional attachment and securing elements are omitted, viz. screwspikes 9, spikes 7 and fish-plate bolts 12, their function being superseded by the mutual bonding of elements in mutual contact by using a filling material having bonding properties.

Thus, in the attachments of rail section 2, the fish-plate bolts 12 are omitted, also the screw-spikes 9; and the anti-creep devices 13, 14 have a different form, and besides performing their normal function, also replace the conventional spike 7, being inserted into the tie and bonded to it by the method of the invention. Both the anti-creep devices 13, 14 are in the form of simple fingers with their upper ends bent over to engage the railbase. In one case (13) the finger is inserted through an opening in the placed close alongside one of the tie-plates lateral edges.

The gap between the abutting ends of the rail-sections 1, 2 is made as small as is practicable and is filled with a filling material 5 of the kind herein specified. Similarly, the cover strip 4 is bonded to the rail-sections 1 and 2 with the specified material.

The omission, from the structure illustrated in the righthand half of FIGURE 1, of some of the conventional securing elements, eg bolts 12, screw-spikes 9 and spikes 7, is made possible by using the joint forming method of this invention, because this latter method ensures a mechanically continuous and effective joint between all the pairs of elements having surfaces in mutual contact, viz. 2, 4; 2, 3; 2, l3; 2, 14; 2, 15, 6; and the interconnection between the rail-sections 1, 2 by means of a filling of bonding material 5 establishes mechanical continuity between them, equivalent to that of a welded joint.

In some cases, e.g. for light railways and so-called Decauville tracks, using metal ties, the tie-plates may be omitted and the rail-base bonded directly to the ties by filling and bonding material of appropriate properties.

In practice it may be more convenient, if not absolutely necessary, to use the conventional securing means such as the spikes 7, screw-spikes 9 and bolts 12 to hold together the various elements of the structure illustrated in the right-hand half of FlGURE 1 during the assembling process, the securing means in question being removed after the filling and bonding material has hardened and formed a strong mechanical bond between the joint surfaces of the several elements.

Whereas the conventional anti-creep devices 10, 11 are held in place by being sprung over the rail foot so as to exert a powerful gripping action on the latter, the anticreep devices l3, 14 do not embrace the rail-base and are not prestressed in the same Way, but are fixed to the railbase solely by the filling and bonding material, the high shear-strength of which prevents endwise creep of the rail.

To obtain a joint of the greatest possible rigidity etWeen the rail and the fish-plate, it is advisable to provide an interference fit between the fish-plate and the rail, the emplacement of the fish-plate being effected by diiierentially heating it and the rail in situ, a quite moderate temperature difference being enough to produce an adequate interference fit when the temperatures equalize. This procedure also promotes a very thorough filling of the fishing surfaces of the joint by squeezing the filling material so as to fill any small interstices due to irregularities of the joint surface while the material is curing, as hereinafter more fully explained.

For forming a joint filling (or an intermetallic bond) in this case the proprietary products Araldite 123-B and Hardener (Durcisseur) 953-13 are preferred; and a preferred procedure is as follows:

First thoroughly scour and clean the butt ends of the rails and the joint surfaces of the rails and fish-plates, e.g. by sand or shot blasting; lay the rails end to end; heat tie-plate 15, and in the other (14) it is,

the rails (in situ) to about 60 C. and the fish plates separately to about 40 C.; spread a previously prepared paste consisting of a mixture in substantially equal parts of Araldite 123-13 and Hardener 953-B on the fishing surfaces of the fish-plates and force the paste between the butt ends of the rails; but the fish-plates in position and tighten the fish-plate bolts are much as possible (the differential expansion due to the temperature difference of about 20 C. enables the fish-plates to be driven deeper into the rail channels, between head and foot than if their temperatures were equal); then heat the whole joint to a temperature suifioient to produce quick curing of the paste-at 180 C. complete curing will take 3 to 5 minutes, at C. 5 to 10 minutes, whereas at 20 to 25 C. 36 to 48 hours are required.

The heating of the joint to an even temperature through out causes the fish-plates to expand more than the rails, thus establishing the interference fit and squeezing the paste (17, FIGURE la) into the interstices of the joint. On cooling, the interference fit is maintained and the by now cured bonding material confers complete material continuity on the joint, the filling having a high strength in compression and shear.

The above defined mixture forms a paste which can easily be spread by a spatula, brush or any suitable spreader, or even by hand (protection by rubber gloves being desirable in this case) and it can easily be squeezed into the gap between the butt ends of the rails. It will not run either at normal air temperature or when heated so that no shuttering is required. The mixture must be prepared with care; once made, it will keep for one and a half to two hours at about 20 C. Any convenient heating means may be used, e. g. electrical, infra-red radiation or a naked fiamc, for which an ordinary welding torch is quite suitable.

The procedure for assembling the various other joints of the assemblies illustrated in FIGURE 1 may be substantially similar to that described above, the step of differential heating being omitted (except in a special case hereinafter described).

Notwithstanding that the materials used for making materially continuous joints as herein described are, in general, electrically non-conducting, the proprietary products Araldite I and Araldite l23-B being excellent insulators, conducting joints between electrically conducting elements can none-the-less be made, as illustrated for instance in FIGURES 2 and 3, which show a conducting joint between two conducting elements 1 and 3, which may represent a rail and fish-plate, but may also be regarded generally as representing any two elements between which such a joint is required.

In these figures (2 and 3) the joint surfaces are purposely roughened so that when strongly pressed together, as for instance by the bolt 12, the high spots 16 of the joint surfaces (see especially FIGURE 3) make good contact and provide electrically conducting paths of adequately low total resistance. At the same time these points of contact are completely embedded in the filling material 17 which thus protects them from being reached by the atmosphere or percolating moisture, and in consequence sufifering oxidation or other corrosion, while the filling material is itself substantially inert to the chemical actions generally included in the term weathering. Such a conducting joint is very durable and resistant to weathering action and requires very little in the way of periodical inspection, besides eliminating the need for any connector cables as conventionally used, e.g. for connecting abutting sections of conductor rail. When the filling of such a conducting joint has been cured, it is usually preferable to leave the bolt under heavy tension, to maintain the contact pressure on the high spots 16 of the joint faces which provide the conducting paths, but if the material also forms a strong intermetallic bond, this is not essential.

FIGURE 4 illustrates a non-conducting, insulated joint.

As in FIGURE 2, the joined elements are designated 1, 3 held together (initially at least) by a bolt 12. In this case the element 1 is insulated from element 3 and from the bolt 12 by an insulating member 18 in the form of a flanged tube of any suitable insulating material, for instance resin-bonded glass fibre, completely embedded in the filling material 17 which provides the material or mechanical continuity of the joint. As before, the joint surfaces are roughened to key the filling material effectively. nI this case the bolt 12 need only be tensioned to a moderate extent, sufficient to ensure that all interstices of the joint faces are completely filled with the filling material, leaving no voids.

If the filling material has bonding properties, it is possible to withdraw the bolt, such as 12 of an initially bolted joint, such as 1, 3, after curing of the filling and bonding material, provided the bolt is first treated with a coating of material which will not stick to the filling and bonding material, e.g. by dipping the bolt in a silicone bath.

Referring to FIGURES 5, a, 5b, in fitting a conventional anti-creep device, such as in FIGURE 1, to the rail-base and making a filled joint between them, the preliminary step of cleaning the joint surfaces may be omitted, since the surfaces of the rail foot 1 are elfectively cleaned by the scraping action of the sharp leading edges 19 of the anti-creep device 10 when it is driven on to the rail-base by hammering in the direction of arrow 21 in FIGURE 5. As the anti-creep device is driven home into the position shown in FIGURE 5a, some of the filling material 17 previously introduced into its slot (FIGURE 5) remains as a layer between the joint-faces of the rail-base and anticreep device and the bulk of it is squeezed into the end of the slot and completely fills the space at the bottom of the slot (FIGURE 5a). At the same time the limbs of the anti-creep device, which is made of a mild steel and is preferably stiffened by lateral flanges 22, 23 (FIGURE 5b) are sprung apart so as to grip the rail-base elastically. The operations may be facilitated by adopting similar steps to those above-described with reference to FIGURE 1 for making the fish-plate joint, viz. heating the rail to about 40 C. and the creep-stop to about 60 C. before driving home the latter, and then heating both together to about 180 C. for long enough to ensure the curing of the filling material. However, the whole operation can be carried out without heating, provided a long enough time, i.e., 36 to 48 hours, is allowed for curing of the filling material at normal air temperatures, before the track is brought into use.

Since the filling material though strong in compression and shear, is relatively weak in tension, the anti-creep device can be removed without diificulty by prying the joint surfaces apart, an operation which can be facilitated by providing the anti-creep device with notches 24, 25, 24, 25' (FIGURES 5, 5a, 5b) into which the tip of a wedge or lever can be inserted.

The anti-creep device 11 of FIGURE 1 is made of relatively soft, non-springy metal, e.g. mild steel, and relies solely on the bonding property of the filling material to hold it in place, as is also the case with the finger anticreep devices 13 and 14, which latter are preferably clamped in the desired position until the bonding material has been cured.

When it is desired to use as the filling agent a material which at some stage of the process will flow freely, such as the proprietary product Araldite I previously mentioned, or a cement or low-melting point alloy, some form of shuttering will be necessary. FIGURES 6 to 9 illustrate suitable ways of meeting this requirement in filling the joint between abutting rail ends without a fish-plate. In FIGURES 6 and 7 the shuttering is provided by a coupling sleeve 26, made of light, ductile and malleable material, e.g. sheet aluminium or mild steel sheet, which is swaged into place around the rail ends and prevents the filling, or filling and bonding, material from running out of the joint between the rail ends when it is, or becomes, liquid. FIGURES 8 and 9 illustrate alternative forms of coupling sleeve, prefabricated in two or three pieces, thus avoiding the operation of swaging on to the rail ends.

The coupling sleeve of FIGURES 6 and 7 will normally be left in place when the filling material has been cured and may itself be adhered to the rail ends by the filling material (as the latter has bonding properties), thus reinforcing the joint, In such cases, the pre-fabricated coupling sleeves of FIGURES 8 and 9 can, however, be removed for future use, after they have served their main purpose, having been treated in advance with a nonsticking agent as previously mentioned in describing FIGURES 2 and 4.

FIGURES 10 and 11 illustrate a fish-plate rail joint designed for maximum strength and rigidity, in which the fish- plates 103, 104 are shaped to fit the rail channels over their whole width. The gap 112 between the rail ends is made as small as possible and the clamping bolts 105 are left permanently in position. All the spaces between the joint surfaces, including those of the bolts 105, are completely filled by an appropriate filling material as indicated at 109, 110, 111, 112. The rail is laid on the tie-plate 108 in the usual way and secured to the tie 106 by conventional spikes 107 (see above as regards play between spike and rail-base). The tie-plate 108 is separated from the tie by a layer 113 of filling material, which (if of the bonding kind) will bond equally well with metal and wood (or concrete) and in any case preferably has mechanical properties intermediate between those of the tie-plate and the tie, so as to avoid any abrupt discontinuity of mechanical properties at a joint between two elements. The continuous filling (or bond) between the tie-plate and tie also prevents the entry between them of hard particles, derived for instance from the ballast, and liable to cause damage by abrasion or bruising, which as is well known is likely to be the more severe in the case of a joint between materials of unequal resistance to wear and local indentation.

If the ties are of wood it is naturally out of the question to heat them, but the tie-plates may be moderately heated to accelerate the curing of the filling (or filling and bonding) material. However, this would normally cause residual stressing of the joint owing to contraction of the metal on cooling. Such residual stressing can be avoided by filling the joint between the tie-plates and the ties at air temperature and allowing time for the filling material to cure (say 36 to 48 hours) before laying the rails and filling the joints between them and the fishplates, for which heat may then be used to accelerate curing. As before, if the filling material has bonding properties, the screw-spikes securing the tie-plates to the ties may be subsequently extracted if desired, the screwspikes having been pre-treated with a non-sticking agent as previously described.

The filling material in the joints between the rail-base and the tie-plates, and between the latter and the ties has a powerful cushioning effect, owing to its relatively greater elasticity than that of the ties, tie-plates and rails, thereby absorbing noise and vibrations. The filling material can also be used to fill up holes in the ties from which old spikes have been removed. If the filling material has the requisite property of bonding to the substance of Which the ties are made, e.g. Wood or concrete, it also prevents the spikes from being worked loose by vibrations and lifting of the rail.

The loading of the filling material proper with such substances as ground-cork or sawdust to give greater softness or elasticity has already been mentioned in respect of joints between rails, tie-plates and ties. Such fillers, as well as others, e.g. mineral powders, metallic particles, vegetable or mineral or metallic fibres, may also be used generally, wherever appropriate; and in cases where the joint spaces are unusually Wide, shims or other packing 9 pieces may be incorporated in the joint together with the filling material proper.

What I claim is:

1. The method of constructing railway tracks, wherein mutually adjoining elements such as abutting rail ends, rails and fish-plates, rails and tie-plates, rails and anticreep devices, tie-plates and ties are juxtaposed with certain respective surfaces normally contacting, which includes the steps of assembling normally abutting parts of said elements into operational position, interposing between the otherwise contacting surfaces of said mutually adjoining elements a filling material composed predominantly of thermosetting resins of the type including an epoxy group, the filling material being applied in liquid form in such manner as to substantially fill all the interstices of the mutually abutting surfaces of said elements to be adhesively secured to one another, and then curing said material to harden it, the filling material having the property of being capable of accelerated curing under moderate heat, said method including the step of heating ,the elements to be joined, after applying the filling material to the surfaces of said elements, to a temperature sufiicient to bring about rapid curing of the filling material, and producing an interference fit between two joined elements, one male and the other female, by differential heating of said elements and forcibly pressing them together, the female element being raised to a higher temperature than the male element, said higher temperature however not being high enough to cause premature hardening of the filling material, and both elements being subsequently raised, while maintaining the pressure, to the accelerated hardening temperature, the consequent differential expansion of the elements bringing about the interference fit;

2. The method of constructing railway tracks wherein mutually adjoining elements such as abutting rail ends,

rails and fish-plates, rails and tie-plates, rails and anticreep devices, tie-plates and ties are juxtaposed with cer- 10 I tain respective surfaces normally contacting, which includes the steps of assembling normally abutting parts of said elements into operational position, interposing between the otherwise contacting surfaces of said mutually adjoining elements a filling material composed predominantly of thermosetting resins of the type including an epoxy group, the filling material being applied in liquid form in such manner as to substantially fill all the interstices of the mutually abutting surfaces of said elements to be adhesively secured to one another, and then curing said material to harden it, elements to be joined to each other being held together by clamping means until the filling material is fully hardened, the clamping means being pre-treated with a non-sticking agent, such as a silicone, enabling it to be removed after the filling material has fully hardened, I

References Cited in the file of this patent UNITED STATES PATENTS 1,817,733 Brunner Aug. 4, 1931 2,047,007 Dalton July 7, 1936 2,499,134 De Bruyne Feb. 28, 1950 2,679,468 Pitman May 25, 1954 2,690,879 Snyder Oct. 5, 1954 2,703,205 Spencer Mar. 1, 1955 2,707,694 Standring May 3, 1955 2,828,236 West Mar. 25, 1958 2,853,412 Hager et al Sept. 23, 1958 2,970,775 Chapman Feb. 7, 1961 2,974,080 Trible Mar. 7, 1961 FOREIGN PATENTS 698,665 Great Britain Oct. 21, 1953 OTHER REFERENCES Lee and Neville: Epoxy Resins, McGraW-Hill Book Co., New York (1957), pp. 7 and 221.

Claims (1)

1. THE METHOD OF CONSTRUCTING RAILWAY TRACKS, WHEREIN MUTUALLY ADJOINING ELEMENTS SUCH AS ABUTTING RAIL ENDS, RAILS AND FISH-PLATES, RAILS AND TIE-PLATES, RAILS AND ANTICREEP DEVICES, THE TIE-PLATES AND TIES ARE JUXTAPOSED WITH CERTAIN RESPECTIVE SURFACES NORMALLY CONTACTING, WHICH INCLUDES THE STEPS OF ASSEMBLING NORMALLY ABUTTING PARTS OF SAID ELEMENTS INTO OPERATIONAL POSITION, INTERPOSING BETWEEN THE OTHERWISE CONTACTING SURFACES OF SAID MUTUALLY ADJOINING ELEMENTS, A FILLING MATERIAL COMPOSED PREDOMINANTLY OF THERMOSETTING RESINS OF THE TYPE INCLUDING AN EPOXY GROUP, THE FILLING MATERIAL BEING APPLIED IN LIQUID FORM IN SUCH MANNER AS TO SUBSTANTIALLY FILL ALL THE INTERSTICES OF THE MUTUALLY ABUTTING SURFACES OF SAID ELEMENTS TO BE ADHESIVELY SECURED TO ONE ANOTHER, AND THEN CURING SAID MATERIAL TO HARDEN IT, THE FILLING MATERIAL HAVING THE PROPERTY OF BEING CAPABLE OF ACCELERATED CURING UNDER MODERATE HEAT, SAID METHOD INCLUDING THE STEP OF HEATING THE ELEMENTS TO BE JOINED, AFTER APPLYING THE FILLING MATERIAL TO THE SURFACES OF SAID ELEMENTS, TO A TEMPERATURE SUFFICIENT TO BRING ABOUT RAPID CURING OF THE FILLING MATERIAL, AND PRODUCING AN INTERFERENCE FIT BETWEEN TWO JOINED ELEMENTS, ONE MALE AND THE OTHER FEMALE, BY DIFFERENTIAL HEATING OF SAID ELEMENTS AND FORCIBLY PRESSING THEM TOGETHER, THE FEMALE ELEMENT BEING RAISED TO A HIGHER TEMPERATURE THAN THE MALE ELEMENT, SAID HIGHER TEMPERATURE HOWEVER NOT BEING HIGH ENOUGH TO CAUSE PREMATURE HARDENING OF THE FILLING MATERIAL, AND BOTH ELEMENTS BEING SUBSEQUENTLY RAISED, WHILE MAINTAINING THE PRESSURE, TO THE "ACCELERATED HARDENING" TEMPERATURE, THE CONSEQUENT DIFFERENTIAL EXPANSION OF THE ELEMENTS BRINGING ABOUT THE INTERFERENCE FIT.

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