Patent Publication Number: US-7908114-B2

Title: System and method for aligning a railroad signaling system

Description:
FIELD OF THE INVENTION 
     The field of the present invention relates to railroad signaling systems generally, and more particularly, to a system, method and computer readable media for aligning a railroad signal for ease and clarity of viewing. 
     DESCRIPTION OF RELATED ART 
     Railroad signaling systems are used for various functions. For example, railroad signaling systems aligned with the roadway intersecting a railroad typically include railroad signals that flash red light along the roadway to warn drivers of automobiles and pedestrians of an oncoming train. As another example, railroad signaling systems positioned adjacent to and aligned with a railroad track typically support railroad signals (of green and red colors) which serve to warn a locomotive operator of an upcoming condition, such as a nearby locomotive, for example. The green and red colors may indicate safe and unsafe conditions, respectively. In either case, the railroad signals are typically positioned along various vertical, horizontal and diagonal bars of the railroad signaling system. 
     Railroad signaling systems depend on various factors for their effectiveness. One such factor includes proper alignment. For example, a railroad signal may become misaligned and not align with the roadway intersecting the railroad, thereby failing to provide the necessary warning to drivers and pedestrians of an upcoming train and creating a safety hazard. Such misalignment of a railroad signal may arise from one of several causes, such as being struck by a passing train, being struck by a passing vehicle such as a truck, harsh weather and wind, or vandalism. Additionally, railroad signals of railroad signaling systems aligned with the railroad are equally vulnerable to such misalignment, thereby failing to provide a necessary warning to a locomotive operator on an upcoming locomotive, or similar unsafe condition. 
     Current regulations require that a maintenance worker regularly travel to railroad signaling systems, and manually check each railroad signaling system for proper alignment. In some cases, the railroad signaling systems are extremely remote, and thus the cumulative high cost and inefficiency of such regular manual alignment checks is extensive. 
     Accordingly, it would be advantageous, both in terms of cost and time efficiency, to provide a system for automatically checking the alignment of railroad signaling systems, without requiring regular manual alignment checks, and arranging for any necessary alignment. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment of the present invention, a system is provided for aligning a railroad signal. The system includes a tilt device to measure the tilt of the railroad signal, a directional device to measure the direction of the railroad signal, and a controller coupled to the tilt device and the directional device. 
     In one embodiment of the present invention, a method is provided for aligning a railroad signal. The method includes providing a tilt device to measure the tilt of the railroad signal, providing a directional device to measure the direction of the railroad signal, and coupling a controller to the tilt device and the directional device. 
     In one embodiment of the present invention, computer readable media containing program instructions are provided for aligning a railroad signal. The computer readable media includes a computer program code to switch the controller to a calibration mode to measure a correct tilt and a correct direction of the railroad signal in a proper alignment by the tilt device and the directional device, and record the correct tilt and the correct direction in a memory of the controller. Additionally, the computer readable media further includes a computer program code for switching the controller from the calibration mode to a monitoring mode upon recording the correct tilt and the correct direction to determine if one of a measured tilt and a measured direction of the railroad signal exceeds a respective tilt threshold and direction threshold stored in the memory of the controller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more particular description of embodiments of the invention briefly described above will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings, in which: 
         FIG. 1  is a perspective view of an embodiment of a system for aligning a railroad signal; 
         FIG. 2  is a front view of the embodiment of a system for aligning a railroad signal shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of an embodiment of a system for aligning a railroad signal according to the present invention; 
         FIG. 4  is a partial side cross-sectional view of the embodiment of a system for aligning a railroad signal shown in  FIG. 1 ; 
         FIG. 5  is a top view of an embodiment of a system for aligning a railroad signal according to the present invention; 
         FIG. 6  is a top view of an embodiment of a system for aligning a railroad signal according to the present invention; 
         FIG. 7  is a side view of an embodiment of a system for aligning a railroad signal according to the present invention; 
         FIG. 8  is a side view of an embodiment of a system for aligning a railroad signal according to the present invention; 
         FIG. 9  is a flow chart illustrating an exemplary embodiment of a method of operating the system illustrated in  FIG. 1 ; and 
         FIG. 10  is a flow chart illustrating an exemplary embodiment of a method of operating a system for aligning a railroad signal. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates an embodiment of a system  10  for aligning a railroad signal  14 , 16 . A railroad signaling system  12  includes a plurality of railroad signals  14 , 16  coupled to a plurality of elongated members  18 , 20 , 22 , 24 , such as a main vertical bar  18  and respective horizontal support bar  20  for holding a railroad signal  14 , and a main horizontal bar  22  extending from the main vertical bar and respective horizontal support bar  24  for holding a railroad signal  16 . The tilt and direction of the railroad signal  14 , 16  may be adjusted by correspondingly adjusting one of a cantilever, fulcrum, or other adjustment device that couples the horizontal support bars  20 , 24  to each respective railroad signal  14 , 16 . Although  FIG. 1  illustrates a main vertical bar  18  and main horizontal bar  20 , the system  10  is not limited to aligning railroad signals for railroad signaling systems with this arrangement, and may be utilized with a main vertical bar without a main horizontal bar, a main horizontal bar without a main vertical bar, or any arrangement of elongated members supporting railroad signals. Additionally, although  FIG. 1  illustrates a plurality of elongated members supporting a plurality of railroad signals, the system  10  may be utilized with a single elongated member or a single railroad signal, as appreciated by one of skill in the art. 
     The system  10  may be used to align a variety of railroad signals  14 , 16 . For example, the system  10  may be used to align railroad signals of a railroad signaling system, such as the railroad crossing signaling system  12  illustrated in  FIG. 1 , with the roadway  40 . The system  10  may achieve a proper alignment such that pedestrians and drivers in cars on the roadway approaching the railroad  26  clearly see the railroad signals  14 , 16 . Additionally, the system  10  may be used to align railroad signals of a railroad signaling system, such as the railroad signaling system  12  illustrated in  FIG. 3 , with the railroad  26  in a proper alignment such that operators of locomotives traveling along the railroad clearly see the railroad signals  14 , 16 . 
     As illustrated in  FIGS. 1 and 4 , the system  10  for aligning a railroad signal of a railroad signaling system further includes a tilt device  28  to measure the tilt of the railroad signal  14 . The tilt device  28  may include any device capable of measuring the tilt of the railroad signal  14 , such as an accelerometer, for example. In an exemplary embodiment of the system  10 , a 3-axis DC-coupled accelerometer is used to measure the tilt of the railroad signal. The tilt device  28  may be positioned at the rear face of the railroad signal  14 , as illustrated in  FIG. 4 , but may be placed at any location along the surface of the railroad signal provided it does not block the transmission of light. Although  FIG. 4  illustrates a tilt device and directional device coupled to the railroad signal  14 , a similar tilt device and directional device is similarly coupled to the railroad signal  16 . Additionally, although  FIGS. 1 and 4  illustrate a single tilt device  28  coupled to the railroad signal  14 , a plurality of tilt devices may be coupled to the railroad signal. 
     Similarly, as illustrated in  FIGS. 1 and 4 , the system  10  for aligning a railroad signal of a railroad signaling system further includes a directional device  30  to measure the direction of the railroad signal  14 . The directional device  30  may include any device capable of measuring the direction of the railroad signal, such a compass, for example. In an exemplary embodiment of the system  10 , an electronic compass is used to measure the direction of the railroad signal. Although  FIGS. 1 and 4  illustrate a single directional device  30  coupled to the railroad signal  14 , a plurality of directional devices may be coupled to the railroad signal. 
     As illustrated in  FIGS. 2 and 4 , the system  10  for aligning a railroad signal of a railroad signaling system further includes a controller  32  coupled to each tilt device  28  and each directional device  30 . As illustrated in the exemplary embodiment of  FIG. 4 , each controller  32  is coupled to each tilt device  28  and directional device  30  by a wire coupling  33  to accommodate transmission of data, as discussed below. Although  FIG. 2  illustrates the controller  32  positioned at the base of the main vertical bar  18 , the controller may be positioned at any location along the railroad signaling system  12 , including at any location along each elongated member. Additionally, although  FIG. 2  illustrates a single controller  32  coupled to all railroad signals  14 , 16 , an individual controller may be positioned adjacent to the railroad signal and individually coupled to each respective tilt device and positional device. Although  FIG. 4  illustrates the tilt device  28  and directional device  30  coupled to the controller  32  via a wire coupling  33 , the tilt device and directional device may be wirelessly coupled to the controller, such as via transceivers, for example, or any other mode of communication appreciated by one of skill in the art. 
     In the exemplary embodiment illustrated in  FIG. 2 , the controller  32  and remote terminal  50  may wirelessly communicate an alert signal  48  via transceivers  31 , 51  respectively positioned on the controller and remote terminal  50 , or by any other method of communication appreciated by one of skill in the art. 
     Each controller  32  is switchable between a calibration mode and a monitoring mode. The controller  32  may be switched between modes manually using a manual switch when a worker visits the railroad signaling system to align the railroad signals, or it may be switched between modes using an automatic switch and automatic steps for performing calibration. Additionally, the controller  32  may be switched between modes by receiving a signal over a wired or wireless network, for example. 
     Upon switching the controller  32  into the calibration mode, the railroad signal  14 , 16  is aligned in a proper alignment for which the railroad signal performs a safe operation. For example, a proper alignment of the railroad signal  14  of  FIG. 1  includes aligning the railroad signal  14  along the roadway  40  such that drivers in automobiles on the roadway and pedestrians on the roadway approaching the railroad  26  clearly see the railroad signal  14 . In an exemplary embodiment of the system  10 , a proper alignment of the railroad signal  14  includes aligning the railroad signal  14  with the roadway  40  such that the direction of the railroad crossing signal does not diverge with respect to the roadway, and the tilt of the railroad crossing signal ensures that the railroad crossing signal is substantially parallel with the plane of the roadway. Upon aligning the railroad signal  14 , 16  in a safe alignment, including a correct tilt  37  ( FIG. 7 ) and correct direction  35  ( FIG. 5 ), the tilt device  28  and directional device  30  respectively measure each correct tilt and correct direction, and communicate the correct tilt and correct direction to the memory  38  of the controller  32  via the wire coupling  33 . Each correct tilt  37  and correct direction  35  is recorded in the memory  38  of the controller  32  upon receiving each piece of data from the tilt device  28  and directional device  30 . In an exemplary embodiment of the system  10 , a 3-axis DC-coupled accelerometer  28  is utilized for the tilt device and an electronic compass  30  is utilized for the directional device. The correct tilt  37  and correct direction  35  of the railroad signal  14 , 16  is recorded in the memory  38  of each controller  32  and respectively includes the three vector components of the gravitational pull on the railroad signal  14 , 16  in three dimensions and an angular direction of the railroad signal  14 , 16 . Upon recording the correct tilt  37  and the correct direction  35  in the memory  38  of each controller  32 , each controller switches out of the calibration mode into the monitoring mode. When operating in the monitoring mode, the controller  32  regularly samples measured tilt and measured direction of the railroad signal  14 , 16  from the tilt device  28  and directional device  30  via the wire coupling  33 . The controller  32  may sample the measured tilt and measured direction data of the railroad signal  14 , 16  from the tilt device  28  and directional device  30  at an adjustable sample rate. 
     For each measured tilt and measured direction communicated from the tilt device  28  and directional device  30  to the controller  32 , the controller determines if one of the measured tilt and a measured direction exceeds a respective tilt threshold and direction threshold stored in the memory  38  of the controller. To determine if the measured tilt or measured direction of the railroad signal  14 , 16  exceeds a respective tilt threshold or direction threshold, each controller  32  detects the presence of a mean shift over a time duration of one of tilt and direction. In an exemplary embodiment of the system  10 , a tilt mean shift over a time duration includes a shift of the tilt vector mean of the railroad signal  14 , 16  in three dimensions as measured by the DC-coupled accelerometer  28  beyond the respective three dimensions of the tilt threshold. In an exemplary embodiment of the system  10 , a directional mean shift over a time duration includes a shift of the vector mean of the railroad signal  14 , 16  angular direction as measured by the electronic compass  30  beyond a respective angular direction threshold. In detecting the presence of a mean shift over a time duration of one of tilt and direction, the controller  32  negates transient vibrations of the railroad signal  14 , 16  during the time vibration. The time duration is thus set to be long enough to avoid consideration of such transient vibrations, yet short enough to provide meaningful calculations of each tilt mean shift and direction mean shift at each time. 
     In an exemplary embodiment of the system  10 , when the controller  32  switches into the monitoring mode, the controller determines whether one of a measured tilt and measured direction of the railroad signal  14 , 16  exceeds a respective tilt threshold and direction threshold by collecting the measured tilt data and the measured direction data, and processing the measured tilt data and the measured direction data with an error detection filter  44 . The data output from this filtering process indicates whether the measured tilt data and the measured direction data respectively exceed the tilt threshold and the direction threshold. 
     Railroad signaling systems are commonly located at the intersection of roadways and railroads, as discussed above. The intersection of roadways and railroads have various arrangements, each of which present unique challenges to correctly aligning the railroad signals of the railroad signaling systems positioned at the intersection. For example, some roadways intersect railroads at a non-orthogonal angle, and thus require calibration to a correct direction with that non-orthogonal angle. As another example, some roadways intersect railroads at an inclined angle, instead of a common leveled-roadway. Such roadways thus require calibration to a correct tilt with the inclined angle of the roadway, for example. 
     Upon detecting that either the measured tilt or measured direction from the respective tilt device  28  and direction device  30  exceeds a respective tilt threshold and direction threshold, the controller  32  switches from the monitoring mode into an alert mode. In an exemplary embodiment of the system  10  illustrated in  FIGS. 5 and 6 , the controller  32  is initially switched to the calibration mode prior to the monitoring and alert modes and the railroad signal  14  is aligned with a correct direction  35  along the roadway  40 . In the exemplary embodiment of  FIGS. 5 and 6 , the roadway  40  makes a non-orthogonal angle with the railroad  26 , however the roadway may make a substantially orthogonal angle with the railroad. The railroad signal  14  may subsequently be rotated beyond the direction threshold and become misaligned, as illustrated in  FIG. 6 , due to a number of reasons, including contact with a passing locomotive, contact with passing automobiles and trucks, and vandalism, among other reasons. In  FIG. 6 , the direction of the railroad signal  14  has changed but the tilt of the railroad signal (in the plane of the figure) remains unchanged. The direction device  30  measures the misaligned direction of the railroad signal  14  and communicates the measured direction data to the controller  32 , which detects that the mean of the railroad signal direction has shifted beyond the direction threshold. Hence, controller  32  switches from the monitoring mode into an alert mode upon the railroad signal  14  rotating to vary the measured direction beyond the direction threshold, despite that the railroad signal  14  does not tilt to vary the measured tilt beyond the tilt threshold. 
     In the exemplary embodiment of  FIGS. 7 and 8 , the roadway  40  may rise at an uphill incline to the railroad  26 , however the roadway may lower at an incline to the railroad or approach the railroad from a substantially level angle. In the exemplary embodiment of  FIGS. 7 and 8 , the controller  32  is first switched to the calibration mode and the railroad signal  14  is aligned with a correct tilt  37  with the roadway  40 . The railroad signal  14  may be subsequently tilted beyond the tilt threshold, as illustrated in  FIG. 8 , due to a number of reasons, including contact with a passing locomotive, contact with passing automobiles and trucks, and vandalism, among other reasons. In  FIG. 8 , the tilt of the railroad signal  14  has changed to an incorrect tilt  38  but the direction of the railroad signal (in the plane of the figure) remains unchanged. The tilt device  28  measures the tilt of the railroad signal  14  and communicates the measured tilt data to the controller  32 , which detects that the mean of the railroad signal tilt has shifted beyond the tilt threshold. Hence, controller  32  switches from the monitoring mode into an alert mode upon the railroad signal  14  tilting to vary the measured tilt beyond the tilt threshold, despite that the railroad signal  14  does not rotate to vary the measured direction beyond the direction threshold. 
     In the illustrated embodiment of the system  10  of  FIG. 2  and  FIGS. 5-8 , upon each controller  32  switching into the alert mode, each controller may send an alert signal  48  to a remote terminal  50  to request realignment of the railroad signal  14 , 16  to the proper alignment with the correct direction  35  and correct tilt  37 . In an exemplary embodiment of the system  10 , upon the remote terminal  50  receiving an alert signal  48 , an operator of the remote terminal may arrange to dispatch a maintenance worker to realign the railroad signal  14 , 16  by adjusting the tilt and direction of the railroad signal to achieve a correct direction  35  and correct tilt  37 . In an exemplary embodiment of the system  10 , such a maintenance worker may adjust the tilt and direction of the railroad signal  14 , 16  using at least one of a fulcrum and cantilever coupling the railroad signal to each elongated member  18 , 20 , 22 , 24 . 
       FIG. 9  illustrates a method  100  for aligning a railroad signaling system  12 . As illustrated in the flow chart of  FIG. 9 , the method  100  begins at block  101  by providing (block  102 ) a tilt device  28  to measure the tilt of the railroad signal  14 , 16 , followed by providing (block  104 ) a directional device  30  to measure the direction of the railroad signal  14 , 16 . Subsequently, the method  100  includes coupling (block  106 ) a controller  32  to each tilt device  28  and each directional device  30 . As stated above, one controller may be coupled to all tilt devices and directional devices, as illustrated in  FIG. 2 , or an individual controller may be respectively coupled to each tilt device and directional device. 
     Upon coupling a controller  32  to each tilt device  28  and directional device  30 , the method may further include switching (block  108 ) a controller  32  to a calibration mode to measure a correct tilt  37  and a correct direction  35  of the railroad signal  14 , 16  in a proper alignment by each tilt device  28  and each directional device  30 , and record the correct tilt  37  and the correct direction  35  in a memory  38  of each controller  32 . The method  100  subsequently involves switching (block  110 ) each controller  32  from the calibration mode to a monitoring mode upon recording the correct tilt  37  and the correct direction  35  to determine if a measured tilt or a measured direction of the railroad signal  14 , 16  exceeds a respective tilt threshold and direction threshold stored in the memory  38  of the controller  32 . 
       FIG. 10  illustrates a method  200  for aligning a railroad signal  12 . As illustrated in the flow chart of  FIG. 10 , the method  200  includes switching (block  202 ) a controller  32  into a calibration mode. After switching the controller  32  into a calibration mode, the method  200  includes measuring (block  204 ) a correct tilt  37  of the railroad signal  14  with a tilt device  28  coupled to the railroad signal  14 , and measuring (block  206 ) a correct direction  35  of a railroad signal with a direction device  30 . Upon respectively measuring the correct tilt and correct direction  37 , 35  of the railroad signal  14 , the method may include setting (block  208 ) a tilt threshold or setting (block  210 ) a direction threshold based on the respective correct tilt and correct direction. Upon measuring the correct tilt and correct direction  37 , 35 , the method includes recording (block  212 ) the correct tilt and correct direction  37 , 35  in a memory of the controller  32 . 
     As illustrated in the exemplary method embodiment of  FIG. 10 , upon recording the correct tilt and correct direction  37 , 35  in a memory of the controller  32 , the method  200  may include switching (block  214 ) the controller  32  into a monitoring mode. Upon switching the controller  32  into the monitoring mode, the method  200  includes determining (block  216 ) whether a measured tilt of the railroad signal  14  exceeds a tilt threshold stored in the memory of the controller  32 , and the method further includes determining (block  218 ) whether a measured direction of the railroad signal  14  exceeds a direction threshold stored in the memory of the controller  32 . Upon determining whether a measured tilt or measured direction of the railroad signal  14  exceeds a respective tilt threshold or direction threshold, the method  200  may include switching (block  220 ) the controller  32  into an alert mode to output an alert signal, automatically adjusting (block  222 ) the railroad signal to position the railroad signal in one or both of the correct tilt and the correct direction and scheduling (block  224 ) a manual repair of the railroad signal tilt and/or direction. 
     Based on the foregoing specification, one or more of the above-discussed embodiments of the invention may be implemented using computer programming or engineering techniques that include computer software, firmware, hardware or any combination or subset thereof, wherein the technical effect is to align a railroad signal so that it can be easily and clearly seen by operators of locomotives and/or automobiles. Any such resulting program, having computer-readable code means, may be embodied or provided within one or more computer-readable media, thereby making a computer program product, i.e., an article of manufacture, according to the discussed embodiments of the invention. The computer readable media may be, for instance, a fixed (hard) drive, diskette, optical disk, magnetic tape, semiconductor memory such as read-only memory (ROM), etc., or any transmitting/receiving medium such as the Internet or other communication network or link. The article of manufacture containing the computer code may be made and/or used by executing the code directly from one medium, by copying the code from one medium to another medium, or by transmitting the code over a network. 
     One skilled in the art of computer science will easily be able to combine the software created as described with appropriate general purpose or special purpose computer hardware, such as a microprocessor, to create a computer system or computer sub-system of the method embodiment of the invention. An apparatus for making, using or selling embodiments of the invention may be one or more processing systems including, but not limited to, a central processing unit (CPU), memory, storage devices, communication links and devices, servers, I/O devices, or any sub-components of one or more processing systems, including software, firmware, hardware or any combination or subset thereof, which embody those discussed embodiments the invention. 
     This written description uses examples to disclose embodiments of the invention, including the best mode, and also to enable any person skilled in the art to make and use the embodiments of the invention. The patentable scope of the embodiments of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.