Abstract:
A cable trough for installing cables alongside a railway line or other right of way is described. The cable trough is constructed using longitudinally oriented reinforcing fibers coated with polymeric resin that generally aligns the reinforcing fibers with the length of the cable trough. One or more connector clips may be used to secure respective portions of the cable trough to one another. The cable trough is provided with a cover that may be removably secured to an elongate channel to protect the cables housed within the cable trough. Elbows, corners, tees, and other connectors may be provided to run the cable trough in any desired direction. A method of installing cables in a cable trough is also described.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. patent application Ser. No. 10/495,500, filed May 13, 2004, which issued as U.S. Pat. No. 7,034,227 on Apr. 25, 2006, and which claims the benefit of Provisional Application Ser. No. 60/404,688 filed Aug. 19, 2002, and priority to International PCT Application Serial No. PCT/US03/25867, filed Aug. 19, 2003. 

   TECHNICAL BACKGROUND 
   The disclosure relates to a conduit system adapted for containing and protecting various types of wiring laid alongside, beneath, or otherwise adjacent to railroad tracks. 
   BACKGROUND 
   Railroad lines provide an ideal location for the placement of various types of cabling. Included in this group are electrical cables and other types of communication cabling. However, because of the nature of the materials from which railway lines are constructed, it is inadvisable to simply bury a cable beneath a railroad line. The pressures and abrasive action of the ballast used to support railway lines quickly degrade any cables buried without protection. In addition, repairs to cabling may interfere with the travel of trains over the railway lines. 
   Various types of conduit have been provided for the protection of cables laid alongside or beneath rail lines. Examples include extruded plastic, pre-cast concrete, cast-in-place concrete, molded composite materials having random orientation of fiber-reinforcing strands therein, and steel. Concrete, both pre-cast and cast-in-place, is extremely heavy and therefore installation may be quite expensive. Extruded plastic cable troughs, both unreinforced and reinforced with randomly oriented fiber strands, have relatively low strengths and, accordingly, shorter life spans and reduced ability to withstand the rigors of installation adjacent a railway lines. Cast or molded thermoplastic materials having randomly oriented fibers tend to be somewhat stronger than unreinforced types of cabling trough, but are quite expensive. Steel cable trough can also be quite expensive. Accordingly, there is recognized a need for a cable trough for railway cabling that has high strength and is lightweight and durable and yet which is inexpensive. 
   These and other objectives and advantages will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. 
   SUMMARY OF THE DISCLOSURE 
   The cable trough disclosed herein embodies an elongate channel that has a bottom and a pair of sidewalls that extend upwardly therefrom in a generally parallel relationship with each other. A removable top is adapted to be placed onto the sidewalls and can be secured to the channel in order to enclose cables disposed within the channel. Preferably, both the channel and the top of the cable trough are formed of a thermosetting resin having contained therein generally uniformly longitudinally oriented reinforcing fibers. These materials are fabricated into the cable trough, preferably using a pultrusion process. 
   Respective lengths or sections of the channel from which the cable trough is made are connected to one another by one or more, and preferably three, connecting clips that are secured between the sidewalls and/or bottom of the respective sections in order to connect them to one another. The connecting clip has a central web with a first and second edge and a pair of stringers that are connected to the first and second edges. The stringers are spaced apart by the web and are generally parallel to one another. The stringers and the web together form a pair of diametrically opposed mouths that are adapted to clamp therein a sidewall or bottom of the channel or the cover of the cable trough. In general, the connecting clip has an “H”-shaped cross-section. One benefit to the use of this type of connecting clip is that no tools are required to assemble a run of the cable trough. 
   The cable trough is relatively simple to install. A method for installation of the cable trough begins with identifying the path where the cables must be run. A first and then a second or subsequent section of the cable trough will then be emplaced along the path along which the cable is to run in an end-to-end relationship. At least one of the connecting clips is installed between the respective ends of each subsequent section of cable trough in order to secure the sections to one another. Once the channel portion of the cable trough has been installed, the requisite cables are laid within the trough and the cable trough covers are placed onto the channel sections of the cable trough and removably secured thereto in order to protect the cables from the exterior environment. 
   It is to be understood that the cable trough may take many shapes and forms, including elongate straight sections, curved sections, T-connectors, and other variously shaped connectors and runs. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded cross-sectional perspective view of a typical cable trough illustrating the relationship between the channel of the trough and its cover. 
       FIGS. 2   a - 2   c  illustrate a T-section, a 45° bend, and a 90° bend in the cable trough, respectively. 
       FIG. 3  illustrates an H-clip of the type used to assemble two sections of cable trough. 
       FIG. 4  illustrates a cross-sectional view of a cable trough according to another embodiment. 
       FIG. 5  illustrates a perspective view of the cable trough of  FIG. 4 . 
   

   DETAILED DESCRIPTION 
   Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice various embodiments, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While certain embodiments have been described, the details may be changed without departing from the invention, which is defined by the claims. 
   Cable trough is typically installed alongside railway lines, either above grade or below grade, depending on the application. Above-grade installations of cable trough may be made directly on the surface of the ballast that supports a railway line, or in an elevated position where the cable trough has been secured to, for example, the wall of a railway tunnel. 
     FIG. 1  illustrates a cross-section of a typical cable trough constructed and arranged according to one example embodiment. Note that any dimensions appearing in the figures are by way of illustration only and it is to be understood that the embodiments disclosed herein are not limited to those dimensions. The cable trough  10  essentially comprises a channel  12  having a top such as cover  14 . The channel comprises a pair of generally vertical sidewalls  16  extending upwardly from and secured to a bottom such as base plate  18 . Each of the sidewalls  16  has on an inner surface thereof an inwardly extending lip  20  that may be formed continuously along the sidewall  16  or in certain predetermined locations as desired. The lip  20  serves as a part of a closure mechanism that retains the cover  14  on the channel  12  once the cable trough  10  has been installed. 
   The cover  14  essentially comprises an elongate plate  22  that has a width and length that are commensurate in scope with those of the channel  12 . The plate  22  has a pair of channel members  24  that extend downwardly therefrom and which engage the upper edges of the respective sidewall  16  of the channel  12 . Note that the channel members  24  address both sides of the upper edge of the sidewalls  16 . In  FIG. 1  the cover  14  and channel  12  are shown in their disassembled position. 
   When the cover  14  has been seated firmly onto the channel  12 , with the upper edges of the sidewalls  16  seated within the channel members  24  of the cover  14 , one or more connector bolts may be passed downwardly through the cover through countersunk bores  26  formed therein. The connector bolts (not shown) have a cam or other offset projection extending from a distal end thereof such that when the connector bolt is rotated, as by screwdriver or the like, to a closed position, the cam or projection will be positioned beneath the lip  20  of the sidewall  16 . When in its closed position, the connector bolts will secure the top  14  to the channel  12  to complete the cable trough  10 . As can be appreciated, cabling, whether electrical, mechanical or fiber optic, is laid in the channel  12  of the cable trough  10  before the cover  14  is placed thereon. 
   It should be understood that the cable trough  10  is not waterproof as such. Accordingly, in order to prevent the accumulation of water and ice inside the channel  12  of the cable trough  10 , one or more drain holes  15  may be formed through the bottom of the trough to allow water to exit the channel  12 . 
     FIGS. 2   a - 2   c  illustrate various types of connectors that may be interposed between straight sections in order to run the cable trough  10  around corners and to create slightly more complex networks.  FIG. 2   a  illustrates a simple tee  30 .  FIG. 2   b  illustrates a 45° bend  32  and  FIG. 2   c  illustrates a 90° bend  34 . It is to be understood that the connectors illustrated in  FIGS. 2   a - 2   c  are exemplars only, and many more connectors useable with the cable trough  10  may be created for use therewith. 
     FIG. 3  is a schematic view of the cable trough  10  of the illustrating how two sections of the cable trough  10  are secured to one another. As can be seen in  FIG. 3 , successive sections of cable trough  10  are laid end to end. One or more clips  40  are used to connect the respective bottom surfaces  18  and sidewalls  16  of the cable trough portions  10 . The clips  40  are generally “H” shaped in profile having a central web  42  that connects first and second stringers  44  and maintains them in a generally parallel relationship with one another. These stringers  44  are spaced apart or otherwise constructed and arranged to resiliently clamp the sidewalls  16  of the respective cable trough portions therebetween. It is preferred to utilize a single clip  40  for each sidewall  16  and bottom  18  in order to connect the successive portions of cable trough  10 . The assembly of the successive portions of cable trough  10  may be achieved without the use of tools, the clamping action of the clips  40  working in conjunction with the weight of ballast typically placed on or around the cable trough  10  to maintain the cable trough  10  in its assembled state. 
   The method of assembling cable trough  10  comprises the steps of emplacing a first portion of cable trough in a predetermined position and emplacing a second portion of cable trough  10  in the second predetermined position adjacent the first portion of cable trough such that the end portions of the cable trough are adjacent one another. The clips  40  are attached to the end of the first portion of cable trough  10  and the end of the second portion of cable trough is then inserted into the remaining free ends of the clips  40  to secure the two portions of cable trough to one another. Note that this process is essentially the same for connecting straight portions of cable trough  10  as for connecting straight portions to connectors, or connectors to connectors. Once the portions of channel  12  have been secured to one another and the desired cabling has been placed therein, complementary covers  14  are placed onto the channels  12  of the cable trough  10  and secured thereto using connector bolts passed through countersunk bores  26  in the cover  14 . 
   In order to achieve a suitable level of strength the channels  12  of the cable trough, and preferably the connectors as well, are produced using an extrusion method commonly referred to as pultrusion. Essentially, continuous strands of reinforcing fibers, typically glass, although other types of reinforcing fibers may be used, are coated or wetted with a heat-curable thermosetting polymeric resin and then pulled through a forming die. The forming die is heated so as to set and cure the resin in the desired shape. The benefit to using this pultrusion method is that the reinforcing fibers present within the sidewall  16  and bottom  18  of the channel, and also those reinforcing fibers present in the cover  14 , run longitudinally through these structures, thereby creating a much more rigid structure. The uniformly oriented reinforcing fibers in the cable trough  10  result in greater ultimate strength, rigidity, and lower deflections. This greater strength and rigidity enables the cable trough to last longer than typical prior art cable troughs made of cast concrete or molded or extruded thermoplastics having randomly oriented reinforcing fibers incorporated thereinto. The increased strength not only improves the cable trough&#39;s resistance to damage, but also results in a longer useful life for the cable trough  10 , thereby greatly reducing its effective cost. 
   Given the flexible nature of the pultrusion process used to produce the cable trough  10 , the geometry of the sidewalls  16 , bottom  18  and cover  14  may be easily changed. This flexibility in manufacturing allows the cable trough  10  to be adapted for varying situations very rapidly and inexpensively. And, because the longitudinal orientation of the reinforcing fibers in the cable trough structures, there is a near exponential increase in the loading capacity of the cable trough  10  per unit increase in the sidewall  16  thickness. This feature of the cable trough  10  allows relatively small changes in the geometry of the trough  10  to account for large variations in the manner in which the trough  10  may be used. This feature also allows this customization to be accomplished relatively inexpensively, as little extra material need be used to realize large increases in the strength of the trough  10 . 
     FIGS. 4 and 5  illustrate another embodiment of a cable trough  50  having a top, such as a cover  52 , which defines a channel  54 . The channel  54  is also defined by comprises a pair of generally vertical sidewalls  56  extending upwardly from and secured to a bottom, such as a base plate  58 . Each of the vertical sidewalls  56  has on an inner surface thereof an inwardly extending lip  60  that may be formed continuously along the sidewall  56  or in certain predetermined locations, as desired. The lip  60  serves as a part of a closure mechanism that retains the cover  52  on the channel  54  once the cable trough  50  has been installed. 
   The cover  52  essentially comprises an elongate plate  62  that has a width and length that are commensurate in scope with the length and width of the channel  54 . For example, in the particular embodiment illustrated in  FIGS. 4 and 5 , the plate  62  is approximately 10 inches wide and 120 inches long. The plate  62  has a pair of channel members  64  that extend downwardly from the plate  62  and that engage upper edges of the sidewalls  56 . Note that the channel members  64  address both sides of the upper edge of the sidewalls  56 . In  FIGS. 4 and 5 , the cover  52  and channel  54  are shown in an assembled position. 
   In the embodiment shown in  FIGS. 4 and 5 , angled members  66  connect the sidewalls  56  and the bottom of the cable trough  50 , e.g., the base plate  58 . In the illustrated embodiment, each angled member  66  is positioned at an angle of approximately 72° relative to the base plate  58  and at an angle of approximately 18° relative to the respective sidewall  56 . These angles are not critical, however. For example, in another embodiment, each angled member  66  may be positioned at angles of approximately 45° with respect to both the base plate  58  and the respective sidewall  56 . The angled members  66  add rigidity to the structure of the cable trough  50  and may reduce or prevent deflection of the sidewalls  56 . 
   When the cover  52  has been seated firmly onto the channel  54 , with the upper edges of the sidewalls  56  seated within the channel members  64  of the cover  52 , one or more connector bolts may be passed downwardly through the cover through countersunk bores (not shown in  FIGS. 4 and 5 ) formed therein. The connector bolts (not shown in  FIGS. 4 and 5 ) have a cam or other offset projection extending from a distal end thereof such that when the connector bolt is rotated, as by screwdriver or the like, to a closed position, the cam or projection will be positioned beneath the lip  60  of the sidewall  56 . When in its closed position, the connector bolts will secure the top  52  to the channel  54  to complete the cable trough  50 . As can be appreciated by those of ordinary skill in the art, electrical, mechanical, fiber optic, or another type of cabling may be laid in the channel  54  of the cable trough  50  before the cover  52  is placed thereon. 
   It should be understood that the cable trough  50  is not waterproof as such. Accordingly, in order to prevent the accumulation of water and ice inside the channel  54  of the cable trough  50 , one or more drain holes (not shown in  FIGS. 4 and 5 ) may be formed through the bottom of the trough to allow water to exit the channel  54 . 
   The foregoing is considered as illustrative only of the principles of various embodiments. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While certain embodiments have been described, the details may be changed without departing from the spirit and scope of the present invention, which is defined solely by the claims.