MXPA06009108A - Method for restoring used railroad ties and the restored railroad ties formed thereby. - Google Patents

Abstract

This invention provides a method for restoring at least one means defining a railroad spike hole located in a used railroad tie. In this way, the restored railroad tie can be reused in subsequent rail replacement operations. The restored railroad tie is capable of having a railroad spike penetrate and be retained within the confines of the restored railroad spike hole without substantial bending problems. The used railroad tie provided has at least one spike hole located therein. In each the means defining a railroad spike hole is formed a polymeric plug. The polymeric plug comprises a polymeric plug formed of a polymeric material including a plurality of flexible, readily deformable micro-inclusions which allow the formation of spike insertion pathways that track the insertion forces of the railroad spike as it is driven into a material thereby facilitating introduction of the railroad spike into said polymeric plug. The polymeric plug is capable of penetration by and retention of the railroad spike there within.

Description

METHOD TO RESTORE USED RAILWAY TRAVIES AND RESTORED RAILWAY TRAINS FORMED FROM THE SAME FIELD OF THE INVENTION The invention relates to a method for restoring used railway sleepers having holes for pre-existing nails, and more particularly with a method for plugging the pre-existing nail holes in the railway sleepers used therewith and thus forming the restored railway sleepers which can be reused in rail replacement operations. BACKGROUND OF THE INVENTION All rail maintenance in railway operations typically includes the removal of rail nails from railway sleepers. In many cases, these railway sleepers have the structural capacity to be used because they have not deteriorated to a point where they need to be replaced. However, to reuse these sleepers it is necessary to plug any existing nail holes in the structure of the railway sleeper. Generally, these nail holes can be plugged.

In this way, when the nails are re-driven into the holes, the nails must be anchored firmly confined within the sleepers. Ref. No.:174891 In certain conventional practices, the sleepers are plugged manually by placing a wooden bolt inside the nail holes. Unfortunately, the use of wooden bolts results in several problems. First, the bolts do not completely fill the hole. This causes the filtration of moisture during its use that finally accelerates the putrefaction of the sleeper and in turn the deterioration of the structure of the railway sleepers. Also, compared to the new virgin rail sleepers without using originals, the wooden bolts do not effectively anchor the nails within the structural rail sleeper member. The use of wood substrates and polymeric materials has been described in the prior art, according to the following: Method for Restoring Used Railroad Ties and the Restored Railroad Ties Formed Thereby (U.S. Patent 5,952,072), Process For Producing Filled Polyurethane Elastomers (US Patent 5,952,053), Foamable Composition Instant Thixotropic Geling (US Patent (6,455,605), Method of Filling Spike Holes in Railway Ties (US Patent 4,295,259), which are incorporated herein by reference. It is desirable to provide an effective and efficient method for filling holes for nails in used railway sleepers which will then produce restored filled railway sleepers which can be reused in rail replacement operations, preferably such method should have the following attributes: (a) firmly anchor the nail inside the sleeper; (b) i Deeply filter cracks and small cracks in the wooden surface that forms the nail hole to prevent rotting of the sleeper due to moisture; (c) airtight agglutination with wood to prevent moisture infiltration; (d) having the ability to re-hold a nail in a relatively short time after being supplied; (e) displacing the standing water in the holes of the sleeper during the filling operation of the hole; (f) converting the permeable sleeper holes into dikes to allow complete filling. As for the filled portion of the railway sleeper, the latter should anchor the nail in a way that is comparable to the introduction of a railway nail into a portion of virgin wood of the railway sleeper obj eto. It is of particular importance to provide a hole for filled nail which meets the needs described above but which has the ability to allow the rail nail to penetrate effectively the filled material without significant flexing problems. SUMMARY OF THE INVENTION The needs expressed above have been met with a restored railway sleeper in which the existing nail holes have been filled in accordance with the teaching of the present invention. More specifically, this invention provides a method for restoring at least one means defining a rail nail hole located in a used railway sleeper. In this way, the restored railway sleeper can be reused in subsequent rail replacement operations. The restored railway sleeper has the ability to be penetrated by a railway nail and to be kept confined within the restored rail nail hole without significant flexing problems. The used railway sleeper provided has at least one hole for a railway nail located therein. This invention is directed to a product and method for restoring used railway sleepers having pre-existing nail holes. The product and method object is related to the use of polymeric materials which more effectively and efficiently plug the nail holes resulting in the formation of the completely restored used railway sleeper. The polymeric plug infiltrates and agglutinates hermetically inside the hole for railway nail to avoid infiltration of moisture. In this way, putrefaction of the sleeper by moisture is prevented, and the orifice means for the permeable rail nail is effectively and efficiently converted into a dam to allow a complete filling of the same. The polymeric plug has the ability to be penetrated by, and retain the rail nail within it. The above and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment which is developed with reference to the figures. DETAILED DESCRIPTION OF THE INVENTION A restored used rail crossmember that can be reused in subsequent rail replacement operations and a method for restoring at least one means defining a rail nail hole located in a used rail cross rail is provided. In this way, the restored railway sleeper can be reused in subsequent rail replacement operations. The restored railway sleeper has the ability to be penetrated by a railway nail and to be kept confined within the restored rail nail orifice medium without significant flexing problems. The object method comprises providing the used railway sleeper having at least one medium defined by a rail nail hole located therein. A polymeric plug is formed in each hole for a railway nail. The polymeric plug is formed with a polymeric material that includes a plurality of flexible, easily deformable inclusions which allow the formation of a nail insertion path.

Simultaneously, it allows the insertion of a nail while deforming the wood fiber at the interface between the capping material and the restored railway sleeper. The calculation of the trajectory of the forces during the insertion of the railway nail allows to gain a perception related to the insertion path of the nail. This can be achieved by calculating the trajectory of the forces as the rail nail is driven into the plugging material. The introduction of the rail nail into the polymer plug, which has infiltrated and hermetically bound within the rail nail hole, prevents infiltration of moisture and thereby substantially prevents the putrefaction of the sleeper by moisture. The dike formation of the permeable rail nail orifice is a means to allow complete filling thereof. The flexible inclusions that can be introduced into the material are typically composed of polymeric microballoons. Preferably, the inclusions comprise surface-treated polymer microballoons. More preferably, the treated polymeric microballoons comprise coated polymer microballoons. The most preferred inclusions are polymeric microballoons coated with calcium carbonate. The flexible inclusions may be supplied in an amount of up to about 3.0% by weight, preferably up to about 2.5% by weight, more preferably up to about 2.0% by weight, and most preferably up to about 2.0% by weight, based on the weight total polymeric capping material. It has been found that flexible inclusions, such as the polymer microballoons described above, provide improved interactions between the polymer matrix and the flexible inclusions. In this way, the performance of the material under loading conditions will be improved according to what is determined by a scanning electron microscope image (SEM) after the test load. These inclusions must not exhibit obvious deagglutination nor should they impact in a way that deteriorates the thermal properties of the system material. Dualite MS7000 flexible microballoons can be used as flexible inclusions in this invention. The polymeric material is typically a substantially non-cellular material. Polyureas, polyurethanes and hybrid polyurea / polyurethane polymers are particularly useful in this invention. Preferably, the polymeric material is a polyurethane material. More preferably, the polymeric material is a polyurea material. More preferably, the polymeric material is a poly (urethane-urea) material. These polymers are prepared from various combinations of finished amine resins and hydroxyl end resins which are reacted with an isocyanate material. Preferred polymeric capping materials contain a finished isocyanate polymer to improve the miscibility phase. These terminated isocyanate polymers preferably control the structure of the hardness segments in microscopic regions wherein the isocyanate components tend to congregate in a polyurethane-, polyurea, or poly (urethane-urea) compound. The miscibility phase can be measured with an atomic force microscope (AFM), a tunneled electron microscope, a SEM in conjunction with a chemical attack, or a variable pressure scanning electron microscope. The observed morphology is then related to the mechanical properties measured. The polymeric plug of the subject invention typically has a density greater than about 30 lb / ft3, preferably at least about 40 lb / ft3, more preferably at least about 50 lb / ft3, and more preferably from about 60 lb / ft3, preferably up to about 120 lb / ft3, more preferably up to about 100 lb / ft3, and more preferably up to about 90 lb / ft3.

The polymeric plug can also include other additives. These additives may comprise mineral fillers, glass spheres, glass fibers, ceramic spheres, or solid polymer particles. The polymeric material of this invention which is used to repair a railway nail orifice that exhibits improved rheological characteristics. The presence of these rheological properties allows for increased flow rates of the storage totalizers. The flow rate increases are largely due to a reduction in viscosity and low levels of fluid structure as determined by dynamic rheological experiments. It is also possible to obtain a reduction in wear of the application equipment caused by wear. This can be attributed to the presence of a low viscosity material and the use of less abrasive fillers. The subject polymeric material exhibits an increased storage stability of matter. The improved stability is due to (a) the use of materials with surface energies and surface tensions that are more closely adapted; (b) the judicious use of rheological modifiers. Moreover, improved filling of sites with defects without drainage can be obtained at the repair sites when the polymeric material of this invention is employed.

The polymeric plug of the present invention has a low insertion path for materials within a given density classification. The insertion path allows a complete insertion of the nail without causing a substantial bending of the nail, deviations of the nail from the polymeric material, or excessive damage to the material. Thus, the nail can be introduced while local increases in the density of the wood are formed due to the deformation of the fibers of the material. The presence of an appropriate functional-insertion path is integral with improved nail insertion and retention behavior. The insertion path is characterized as the load against the displacement curve generated when driving a nail into the polymeric material. This property is based on the geometry of the test site when the insertion / extraction forces are evaluated after the polymeric material is introduced into a railway sleeper. With the new approach of this invention, the polymer density levels can be increased since the properties of the polymer itself constitute the main means to control the insertion processes of a railway nail, which is opposite to the conventional approach which is found depending on the presence of a reduced polymer density due to the presence of micro-cellular characteristics. Conventional tests show a reduction of insertion forces at low bending values of preferably up to about 50% in relation to the polymeric materials with the highest proportions currently available in the market. Modified test methods showed a preferred reduction of up to 50% of insertion forces in the initial phase in the insertion process, and a preferred reduction in insertion forces of up to about 30% to complete insertion using methods that allow the isolation of the polymer. Restored used railway sleepers show reduced nail insertion forces in relation to comparable sleepers using existing polymeric plug materials. The insertion path is 20% less than that of the other materials of comparable density, although they maintain the objective resistance and the module values required for this application. When the polymeric plugging material is introduced into the nail holes in the field, they form a stable plug at room temperature by a reaction process of the polymer in place. The lower range of operating temperatures for conducting this on-site reaction typically requires the use of liner heaters for the purpose of facilitating completion of the object polymeric cure step. Nevertheless, the use of line tracer heaters makes plug formation increasingly tedious and difficult for field technicians. Conversely, the formation of the polymer capping material can be conducted within an expanded range of operating temperatures without the use of the line tracer heaters. The line tracer heaters are used to ensure that the holes are filled properly, by increasing the temperature of the mixed resin, thereby reducing the viscosity. - The reduction of the use of the line plotter over a much broader operating temperature range can be achieved through the use of the polymer capping material of this invention. This represents a global simplification of the protocols required for the use of the material by field technicians. Also lower energy requirements for the plug formation equipment (energy saving). Currently the liners are activated for temperatures below approximately 80 ° F (26.6 ° C). Typically the temperatures of the line tracers are set to approximately 90-120 ° F (32.2 - 48.8 ° C). When the subject polymers are employed as a capping material, preferably a line tracer heater is not necessary until the temperature drops to about 40 ° F (4.4 ° C), more preferably about 50 ° F (10 ° C), and more preferably about 60 ° F (15.5 ° C). The rheological profiles of this invention make it possible to avoid the need to use a line tracer heater to reach lower temperatures, for example 40 ° F (4.4 ° C). The nail insertion path calculates the trajectory of the insertion forces of a nail as it is driven into a material. The values can be recorded continuously or at discrete distances with respect to the course of a displacement of the nail within the polymeric material. The polymeric capping material of the present invention shows lower insertion forces than materials of similar density. The interface morphology of the polymeric plugging material employed herein can facilitate improved stress release. Effort release is measured directly by fluence experiments using dynamic mechanical analysis (DMA). It can also be inferred by examining the state of the material by means of an SEM after being subjected to loading in accordance with a prescribed schedule or after a mechanical test. Upon reaching the preferred levels of stress release, a decrease of opposing forces is obtained which act negatively impacting the insertion of a railway nail within the polymeric plug.

For example, these insertion forces can be traced with the use of a mechanical loading machine to drive a nail (railway nail) into a polymer sample. The exemplary test to determine the stress release level may employ a rectangular cross sectional area of 0.5 inches x 0.75 inches (1.27 cm x 1.90 cm), or a circular cross sectional area of 2 inches (5.08 cm), on a railway sleeper . The subject polymeric plug materials also show a lower polyurethane index. The polyurethane index is the ratio of functional equivalents of the isocyanate with the functional equivalents of the alcohol. A lower polyurethane index offers the benefit of reducing cell formation when the material is properly supplied in an aqueous environment. Cell formation can be directly evaluated with the use of SEM techniques. Technicians who use polymeric plug materials will also get the benefit of a product which has a low density. Thus, this polymeric plug material will mix more easily and also allow better penetration into faults in railway sleepers so that the plug formation time will be reduced and it will require less effort by the technician to restore the railway sleeper. For the purpose of this invention, penetration into a fault is measured by filling a fault in a railway sleeper with the polymeric plug material under circumstances that replicate the conditions in the field. Then the railway sleeper is cut transversely or is separated by tearing with a hammer and chisel to directly observe the efficiency of the filling operation of the fault. The used and restored railway sleepers of this description show excellent mechanical properties which are based directly on the strength and relative flexibility of the subject polymeric plug material. These properties also corroborate the tendencies of relative deformation of a material under axial load, shear or compression. Additionally, these properties have shown good performance under load conditions. Performance under load conditions tracks the change in material properties after a schedule of particular loads. A servo-hydraulic loading machine can be used to load a material at different frequencies and forces. Evaluations can also be done with the use of a DMA. A flow rate describes the volume (or mass) of material that will flow under certain conditions. The polymeric object plug materials offer improved flow rates under severe conditions.

The strength of the material should be maximized within the aforementioned elongation and modulus constraints. A minimum stress stress should be at least approximately 2100 psi (147.64 kg / cm2). In order to ensure a good lateral resistance to the load, Compounds of taponador sleeper is provided with a preferred range from about 600 Mpa, more preferably from about 800_ Mpa, preferably up to about 1500 Mpa, more preferably to about 1400 Mpa, and more preferably to about 1200 Mpa module minimum Young. In that way, the polymeric plug material will reach a desirable resistance level with a maximum load while allowing reduced forces which facilitate the insertion of the nail. One of the test methods which can determine the insertion resistance and preferred extraction of a polymeric plug is to analyze a cylindrical sample of 200 cm3 to drive a nail 7-D within the sample using an Instron mechanical test 0.35 in / min (0.889cm / min) (to a depth of 0.7 inches (1.778 cm)). Insertion forces are typically not greater than about 700 lbf (317.5147 kgf), preferably not greater than about 650 lbf (294,835 kgf), more preferably not greater than about 600 lbf (272.1554 kgf), and more preferably not greater than about 500 lbf (226.7962 kgf). The extraction forces also depend on the geometry of the sample. A preferred method for evaluation is to use an Instron mechanical test machine to pull the 7-D nails out at 0.5 inch / min (1.27 cm / min). The minimum extraction force is preferably at least 200 lbf (90,718 kgf), more preferably at least about 150 lbf (68,038 kgf), more preferably at least about 150 lbf (68,038 kgf), and most preferably at least about 100 lbf (45,359 kgf). Additional additives may comprise mineral fillers, glass spheres, glass fibers, ceramic spheres, rubber inclusions, or polymeric spheres. Ideally, the surface energy of the inclusions will adapt with the surface energy of the polymer matrix or they will exhibit good agglutination after application of the mechanical stress as determined by the SEM. Extender materials can also be added to the sleeper corking composition. Preferably, polyols and polyamines can be used for these extender materials, the most preferred extender materials are PPG, PEG, blocked hydroxyl polyesters, castor oil, 2-ethyl-l, 3-hexanediol, and blocked hydroxyl / mine polybutadiene.

EXAMPLE 1 An illustrative example of the method for producing the subject polymeric material for restoring used railway sleepers having holes for pre-existing nails is as follows: Polyol resin preparation procedure: Using a Moorehouse Cowles laboratory mixer equipped with a disc-type blade with a diameter of 3.3 inches (8.382 cm). A 4-quart stainless steel bottle with a diameter of 6.05 inches (15.367 cm) should be used to contain the reagents during the mixing process. Add the following liquids to the empty stainless steel bottle, measuring the appropriate quantities of material in accordance with the mass specifications: Material class Item Grams Polyol Weight Polyol 59.96 Molecular 3000 Polyol Weight Polyol 380.13 Molecular 700 Chain linker PPppgg - 442255 41.90 Chain linker Vestamina IPD 22.07 Chain linker EPI-Cure 3271 3.06 Chain linker 2-ethyl-l, 3-Hexanodiol 84.10 Agent ANTI-TERRA-U 100 2.02 wetting / dispersion antifoam BYK-066N 5.63 Turn on the energy control for the mixer, increase the mixing speed to 750 RPM. Mix the liquids for five minutes. Use a 1-quart empty plastic container for the fumed silica Aerosil and an empty aluminum dosing balance for the pigment, dose the following masses of materials, add them to the stainless steel flask with stirring continue: Material Class Item Grams Modifier of AEROSIL 200 31.98 rheology Pigment Oxide Powder 11.05 Yellow Steel Mix the fumed silica and the pigment inside the liquids for five minutes, increase the mixing speed to 1500 RPM. At the end of the mixing period, reduce the mixing speed to 750 RPM. Use a 1-quart empty plastic container for the modifier Micorna 7, dose the following masses of materials, add them to the stainless steel bottle under continuous agitation: Material class Item Grams Filler MICRONA 7 399.67 (calcium carbonate) Control additive PURMOL 3ST SIEVE 29.54 humidity Catalyst Neodecanato 4.50 Bismuth Catalyst Neodecanato of Zinc 3.23 Modifier of BYK-410 3.30 rheology Mix the reagents inside the fluid for 10 minutes, scrape the excess material from the sides of the mixer back to the volumetric mass of fluid / stirred resin. Use a 1-quart empty plastic container, dose the following masses of polymeric microballoons, add them to the stainless steel bottle under continuous agitation.

Material class Item Grams Micro-globo Dualite MS7000 10.80 Mix the reagents within the fluid for 15 minutes, scrape the excess material from the sides of the mixer back into the volumetric mass of the stirred fluid / resin. Upon completion, remove the polymeric material and place it in a suitable laboratory container. We claim all the modifications that are within the spirit and scope of the appended claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (21)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. 1. A method for restoring at least one medium defined by a rail nail hole located on a used rail cross rail, whereby the restored rail cross rail can be reused in subsequent rail replacement operations, the restored rail cross rail has the capacity to be penetrated by a railroad nail and to be kept confined within the restored rail nail orifice means without substantial bending problems, the method is characterized in that it comprises: providing the used railway sleeper having at least one means defining a nail hole railway located in it; and forming on each means defining a rail nail orifice, a polymeric stopper formed with a polymeric material that includes a plurality of easily deformable, flexible micro-inclusions which allow nail insertion paths for the rail nail as it is driven within a material and thereby facilitate the introduction of the rail nail into the polymer plug, the polymer plug infiltrated and hermetically bonded with the orifice means for rail nail to prevent infiltration of moisture and thereby prevent substantial putrefaction of the sleeper due to the humidity, and damming the hole means for railroads to allow filling to be completed.
2. 2. The method according to claim 1, characterized in that the inclusions comprise polymeric microballoons.
3. 3. The method according to claim 1, characterized in that the inclusions comprise treated polymeric microballoons. The method according to claim 1, characterized in that the treated polymeric microballoons comprise coated polymer microballoons. 5. The method according to claim 1, characterized in that the polymeric material is substantially non-cellular. 6. The method according to claim 1, characterized in that the polymeric material is a polyurethane material. The method according to claim 1, characterized in that the polymeric material is a polyurea material. The method according to claim 1, characterized in that the polymeric material is a poly (urethane-urea) material. 9. The method according to claim 1, characterized in that the polymeric plug has a density from at least about 40 lb / ft3, (0.0064 kg / cm3) to about 120 Ib / ft3 (0.0019 kg / cm3). > The method according to claim 1, characterized in that the polymeric plug further includes additives which include mineral fillers, glass spheres, glass fibers, ceramic spheres, or solid polymer particles. 11. a restored used railway sleeper that can be reused in subsequent rail replacement operations, characterized in that it comprises a railway sleeper having at least one rail nail hole located therein, the restored rail sleeper has the ability to be penetrated by a railway nail and being kept confined within the restored hole for railway nail without substantial bending problems, which comprises; and a polymeric stopper, located in each hole for railroad nail, formed of a polymeric material, the polymeric material includes a plurality of flexible and easily deformable microinclusions which allows nail insertion paths as the rail nail is driven into a material and thereby facilitating the introduction of the rail nail into the polymeric plug and infiltrating it and hermetically agglutinating it with the rail nail hole means to prevent infiltration of moisture and thereby prevent substantial putrefaction of the sleeper due to moisture, and damming the permeable rail nail orifice means to allow full filling thereof. 12. The method according to claim 11, characterized in that the inclusions comprise polymeric microballoons. The method according to claim 11, characterized in that the inclusions comprise treated polymeric microballoons. The method according to claim 11, characterized in that the treated polymeric microballoons comprise coated polymer microballoons. 15. The method according to claim 11, characterized in that the polymeric material is substantially nocellular. 16. The method according to claim 11, characterized in that the polymeric material is a polyurethane material. 17. The method according to claim 11, characterized in that the polymeric material is a polyurea material. 18. The method according to claim 11, characterized in that the polymeric material is a poly (urethane-urea) material. The method according to claim 11, characterized in that the polymeric plug has a density from at least about 40 lb / ft3 (0.0064 kg / cm3) to about 120 lb / ft3 (0.0019 kg / cm3) 20. The method according to claim 11, characterized in that the polymeric plug further includes additives which include mineral fillers, glass spheres, glass fibers, ceramic spheres, or solid polymer particles. 21. A method for restoring at least one means defining a rail nail hole located on a used wood railway sleeper, so that the restored sleeper can be reused in subsequent rail replacement operations, the restored rail sleeper has the ability to be penetrated by a rail nail and keep it confined within the restored rail nail hole means without substantial bending problems, the method is characterized in that it comprises: providing a used rail crossmember having at least one means defining an orifice for railway nail located in it; and forming on each means defining a rail nail orifice, a polymeric stopper formed with a substantially non-cellular polymeric material that includes a plurality of polymeric microballoons which allow the formation of nail insertion paths as the rail nail is driven into a material thereby facilitating the introduction of the rail nail into the polymer plug, the polymer plug is infiltrated and hermetically bonded with the hole means for rail nail to prevent infiltration of moisture thereby preventing substantial putrefaction of the sleeper due to moisture, and dampening the permeable rail nail orifice means to allow full filling thereof.