1. Field of the Invention
The present invention relates to the method and apparatus for electrically isolating two adjoining railroad rail sections together and, more particularly, to providing joined insulated rails that are machined.
2. Description of Related Art
Rail systems are often divided into sections or blocks to permit more than one train to travel on one stretch of rail. The purpose of dividing railroad rails of a rail system into sections is to detect the presence of a train on a section of rail at any given time. Each rail section is electrically isolated from all other sections so that a high electrical resistance can be measured over the rail section when no train is present in that section. When a train enters a rail section, the train will short circuit adjacent railroad rails in which the electrical resistance in the rail section drops, thereby indicating the presence of a train.
Railroad rails are generally welded to each other or attached to each other by a steel joint. Typical railroad rails generally include a body having a head section, a web section, and a base section, with the web section defining an opening for receiving fasteners. In order to electrically isolate adjacent rail sections of a rail system, high-performance, non-metallic joints or steel joints having electrically-insulated material bonded to its surface, are typically used in conjunction with electrically-insulating material placed between abutting ends of joined railroad rails. Through extended use, the wheels of the train will often cause the ends of conventional rails to deform and/or break apart (referred to in the industry as end batter), causing the railroad rails to contact each other and short out.
Certain prior art rail joint arrangements address this problem by providing two joined railroad rails that have been machine cut, tapered, and trimmed to complement each other and form a Z-shaped cut. This arrangement spreads the impact load of the train wheels over a longer area, thus increasing the Moment of Inertia at a section where the railroad rails are joined. Although the arrangement has a high Moment of Inertia, which can be defined as the capacity of a cross-section to resist bending, this arrangement utilizes non-standard railroad rails having a double-thick web section, such that non-standard rail joint bars have to be used when attaching the railroad rails to each other.
In one embodiment, a railroad rail includes a body defining a first section and a tapered second section with the body defining a head section, a web section depending from the head section, and a base section depending from the web section. The head section, the web section, and the base section define an end surface configured to mate with a corresponding end surface of a complementary railroad rail when joined together. The railroad rail is formed from a single bent railroad rail having only a single bend defined by the head section, web section, and base section of the body of the railroad rail.
The web section of the body at the tapered second section may have a thickness that is about constant. The web section of the body at the tapered second section may have a thickness that varies less than 5%. The body may define a first recessed portion that extends downward from a top surface of the head section of the body toward the base section with the first recessed portion ending at an end of the tapered second section that is remote from the first section. The body may define a second recessed portion that extends downward from the top surface of the head section of the body toward the base section with the second recessed portion positioned at the first section of the body. The second recessed portion may end at a position adjacent to the tapered second section.
In another embodiment, a rail joint assembly includes first and second rails each having a body defining a first section and a tapered second section. The body of each of the first and second rails defines a head section, a web section depending from the head section, and a base section depending from the web section. The head section, the web section, and the base section of each rail defines an end surface with the end surface of the first rail configured to mate with the end surface of the second rail when joined together. The first and second rails are formed from a single bent railroad rail having only a single bend defined by the head section, web section, and base section of the single bent railroad rail. The rail joint assembly also includes at least two joint bars configured to be secured to the first and second rails by a plurality of fasteners.
The at least two joint bars may comprise only two bonded joint bars. The end surfaces of the first and second rails may overlap in a transverse direction when joined together. The end surfaces of the first and second rails may overlap for a length of about 15 inches. The at least two joint bars may also comprise two bonded joint bars and two standard joint bars. The end surfaces of the first and second rails may overlap in a transverse direction when joined together. The end surfaces of the first and second rails may overlap for a length of about 30 inches. The web section of the body of each of the first and second rails may have a thickness that is about constant at the tapered second section. The body of each of the first and second rails may define a first recessed portion that extends downward from a top surface of the head section of the body toward the base section with the first recessed portion ending at an end of the tapered second section that is remote from the first section. The body of each of the first and second rails may define a second recessed portion that extends downward from the top surface of the head section of the body toward the base section where the second recessed portion is positioned at the first section of the body. The second recessed portion may end at a position adjacent to the tapered second section.
In a further embodiment, a method for manufacturing a railroad rail end section for use in an insulating rail joint assembly includes providing a railroad rail having a body and defining a head section, a web section depending from the head section, and a base section depending from the web section. The method also includes bending the head section, web section, and base section of the railroad rail, where the head section, web section, and base section of the railroad rail is only bent at a single point. The method further includes machining the railroad rail thereby forming a first section and a tapered second section, where a predetermined portion of the base section, the web section, and the head section of the second section is removed to define an end surface that is configured to mate with a corresponding end surface of a complementary railroad rail when joined together.
The method may also include trimming the machined railroad rail, where a portion of a top surface of the head section of the first section tapers downward toward the base section and, where a portion of a top surface of the head section of the second section tapers downward toward the base section ending at the second end of the second section.
For purposes of the description hereinafter, the words “upward” and “downward”, and like spatial terms, if used, shall relate to the described embodiments as oriented in the drawing figures. However, it is to be understood that many alternative variations and embodiments may be assumed except where expressly specified to the contrary. The specific devices and embodiments illustrated in the accompanying drawings and described herein are simply exemplary embodiments of the invention.
Referring to
Referring to
Referring to
Referring again to
The first and second rails 12, 12′ are mirror images of each other such that the rails 12, 12′, after machining and trimming, complement each other when joined as shown in
Referring again to
Referring to
Referring again to
The first standard joint bar 16 is positioned on the first side 58 of the first rail 12 adjacent to the first bonded joint bar 14. The second standard joint bar 16′ is positioned on the second side 60 of the second rail 12′ adjacent to the second bonded joint bar 14′. The first and second standard joint bars 16, 16′ are secured to the first and second rails 12, 12′ via the plurality of fasteners 18, which extend through the insulating bushings 20 and the respective openings of the first and second rails 12, 12′ and the first and second standard joint bars 16, 16′. The first and second standard joint bars 16, 16′ are non-insulating and do not utilize an insulated sleeve. The rail joint assembly 10 has increased strength properties compared to conventional rail joints. For example, the rail joint assembly 10 may have approximately 58% more bond strength (e.g., shear strength) using the first and second bonded rail joint bars 14, 14′ because of the mating end surfaces 38, 38′. An adhesive can also be used to bond the center rail insulator 52 and the end posts 54, 56 to the corresponding end surfaces 38, 38′ of the rails 12, 12′ to increase the strength of the rail joint assembly 10. The first and second standard joint bars 16, 16′ add stiffness to the rails 12, 12′ by increasing the Moment of Inertia. As shown in
Referring still to
When the rail joint assembly 10 is in use, the train wheels travel on the top surfaces 32, 32′ of the head sections 26, 26′ of the first and second rails 12, 12′. As the train wheels travel from the first rail 12 to the second rail 12′, the second recessed portion 48 of the first rail 12 and the first recessed portion 46 of the second rail 12′, which are positioned adjacent to each other, form a recessed transition area 72 that causes the weight of the train to shift primarily onto the first rail 12 where the web section 28 is thicker. Because the train wheels do not contact the recessed portions 46, 46′, 48, 48′ of the first and second rails 12, 12′, the impact load of the train wheels shift to a portion where the web section 28, 28′ is at its thickest. As the train wheels pass the first recessed portion 46 of the second rail 12′, the load of the train wheels begins to shift to both rails 12, 12′. As the train wheels reach the first recessed portion 46 of the first rail 12, the load of the train wheels shifts primarily to the second rail 12′ where the web section 28′ is thicker. The rail joint assembly 10 results in a stronger and longer lasting assembly having a higher Moment of Inertia relative to conventional rail joint assemblies, thereby reducing the end batter and deformation caused by the train wheels.
Referring to
The rail joint assemblies 10, 80 discussed above and shown in
While several embodiments of a rail joint assembly were described in the foregoing detailed description, those skilled in the art may make modifications and alterations to these embodiments without departing from the scope and spirit of the invention. Accordingly, the foregoing description is intended to be illustrative rather than restrictive.
The present application claims the benefit of U.S. Provisional Application Ser. No. 61/701,185, filed Sep. 14, 2012, the entire disclosure of which is hereby incorporated by reference.
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Number | Date | Country | |
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20140076980 A1 | Mar 2014 | US |
Number | Date | Country | |
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61701185 | Sep 2012 | US |