Abstract:
A wayside lubrication apparatus ( 10 ) for applying a lubricant ( 26 ) to a second position ( 36 ) of a rail ( 12 ) in response to the head of a train ( 14 ) being proximate a first position ( 20 ) of the rail. The distance (D) between the two positions prevents the lubricant from reducing the traction capability of the drive wheels ( 38 ) of the locomotives ( 16 ). The application of the lubricant is terminated before a number of rear load cars ( 46 ) passes the lubricant applicator ( 28 ) so that the residual lubricant remaining on the rail after the train has passed is reduced. Operation of the lubricant dispensing apparatus ( 22 ) may be bypassed by an operator-controlled bypass device ( 60 ) or in response to a signal ( 56 ) indicating moisture on the rail. To avoid excessive lubricant on the rail, a timer ( 42 ) is used to prevent repeated applications of lubricant within a predetermined time period, and/or a lubricant container ( 68 ) is refilled at a controlled rate to proportion the amount of lubricant applied in response to a second consecutive train.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to the field of rail transportation, and more particularly to the field of rail lubrication systems, and specifically to a wayside rail lubrication apparatus and method. 
     BACKGROUND OF THE INVENTION 
     A typical train includes one or more locomotives pulling a plurality of load cars. Each vehicle in the train includes a plurality of metal wheels that roll along the metal rail as the train is propelled along the track. The rolling contact between the wheel and the rail provides an efficient mode of transportation, particularly for heavy loads. Proper interaction between the wheel and the rail is critical for safe, reliable, efficient operation of the train. 
     A rail includes a bottom mounting flange, a top railhead that makes contact with the vehicle wheel, and a flange interconnecting the flange and the railhead. A vehicle wheel includes a center hub mounted onto the vehicle axle, a plate extending outwardly from the hub, and an outer rim surrounding the plate for making contact with the rail. The rim includes an outside diameter tread that may be flat or tapered and a flange extending outwardly from a back side of the tread. The tread rides along a top surface of the railhead for supporting the vertical weight of the vehicle. The flange extends along and makes contact with a side of the railhead for providing lateral support to allow the wheel to follow along the path of the railhead. Flanges are provided on only one side of each wheel along an inside of the rail. As a train negotiates a curve in the track, the flanges of the outer diameter (high side) wheels provide the lateral forces for turning the train. 
     Rail vehicle wheels suffer wear over time due to their contact with the rail. The treads wear as a result of their contact with the top of the rail, particularly in the event of the wheel slipping with respect to the rail during acceleration or braking events. The wheel flanges will wear due to their contact with the inside surface of the railhead, particularly on curves and through switches. It is known in the art to provide lubrication between the wheel and the rail in order to reduce wheel wear and to provide more efficient movement of the wheel over the rail. Lubrication may be provided on the top of the rail to reduce rolling friction at any location. Flange lubrication systems are especially useful in curved areas of the track where the forces between the railhead and the flange are at their maximum. Both on-board and wayside lubrication systems are used. On-board systems are useful for applying lubricant at any location along a rail line. Wayside lubrication systems are typically installed only at curved locations of the track. In some situations, it is desirable to apply lubrication between the wheel and the flange in order to minimize wear of the flange, while at the same time it is undesirable to apply lubrication to the top of the rail because of the reduction in traction that may be generated against a lubricated rail. In general, it is desired to achieve adequate lubrication while minimizing the amount of lubricant used so that the location of the lubricant can be precisely controlled, the cost minimized, and the impact upon the surrounding environment abated. 
     Numerous patents have issued for systems that control the amount, timing and location of lubrication applied between a wheel and a rail. U.S. Pat. No. 6,182,793 describes an on-board lubricant delivery system that changes the rate of application with the speed of the train. U.S. Pat. No. 6,009,978 describes an on-board lubricant delivery system that applies lubrication only when the rail vehicle is on a curved section of track. U.S. Pat. No. 5,896,947 describes an on-board lubricant delivery system that applies flange lubrication at the front of a locomotive and also applies both flange lubrication and top-of-rail lubrication at the rear of the locomotive. This system controls the rate of lubrication in response to train speed, track curvature, trailing tonnage, temperature, direction of travel, status of braking, and high rail verses low rail. U.S. Pat. No. 6,199,661 describes a computer-controlled on-board lubrication system that applies a lubricant only in a quantity that will be consumed by the time the entire train has passed. 
     Wayside lubrication systems are commonly activated by the weight of a passing vehicle. The weight of the vehicle is sometimes used as the source of energy for pumping the lubricant, as described in U.S. Pat. Nos. 4,334,596 and 5,076,396. Known wayside lubricating systems often dispense an inappropriate amount of lubrication and/or dispense lubrication when it is not beneficial. U.S. Pat. No. 4,856,617 describes a wayside lubricating system that incorporates a test cycle to provide compensation for changes in lubricant viscosity as a function of temperature. However, further improvements to wayside lubrication systems are needed. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, a wayside lubrication apparatus is described herein as including a sensor associated with a first position on a rail for producing a lubrication signal when a locomotive pulling a plurality of load cars passes the first position; and a lubricant dispensing apparatus for applying a lubricant to the rail at a second position on the rail in response to the lubrication signal, the lubricant adapted to reduce the friction between wheels of the load cars and the rail, the first position and the second position being separated by a distance on the rail sufficient to prevent the lubricant from contacting drive wheels of the locomotive. In a further embodiment, a wayside rail lubrication apparatus is described as including: a detection apparatus for providing a lubrication signal in response to the presence of a vehicle on a rail; a lubricant dispensing apparatus for applying a lubricant to the rail in response to the lubrication signal; and a bypass device for selectively preventing the lubricant dispensing apparatus from applying the lubricant in response to the lubrication signal. The bypass device may include an operator input device located in the vehicle for controlling the bypass device from the vehicle. 
     A wayside rail lubrication apparatus is further described as including: a lubricant dispensing apparatus for applying lubricant to a rail; and a means for controlling an amount of lubricant applied by the lubricant dispensing apparatus over a predetermined time period. The means for controlling may be a timer for providing a time signal, and the apparatus may include a controller for controlling the operation of the lubricant dispensing apparatus in response to the timer. The apparatus may further include: a lubricant container; a pump for delivering lubricant from the lubricant container to the rail; and a device for refilling the lubricant container with lubricant at no more than a predetermined rate. 
     A wayside rail lubrication apparatus is described as including: a means for applying lubricant to a rail in response to the presence of a vehicle wheel at a location on the rail; and a means for delay associated with the means for applying lubricant for delaying the application of lubricant for a time period after the vehicle wheel is present at the location on the rail. The means for delay may be an empty volume downstream of a lubricant pump. 
     A wayside rail lubrication apparatus is described as including: a sensor for producing a lubrication signal responsive to the presence of a train on a rail, the train comprising a locomotive pulling a plurality of load cars; and a means for applying a lubricant to a section of the rail in response to the lubrication signal only after the locomotive has passed the section of rail. 
     A method of applying lubricant to a rail is described herein as including: applying a first quantity of lubricant to a rail at a first time in response to the presence of a first rail vehicle; sensing the presence of a second rail vehicle at a second time; and applying a second quantity of lubricant to the rail at a second time in response to the presence of a second rail vehicle, the second quantity of lubricant being responsive to the time span between the first time and the second time. 
     A method of applying lubricant to a rail is further described as including: sensing the presence of a train on a rail; applying a lubricant to a section of the rail in response to the presence of the train after a locomotive at a head of the train has passed the section of rail; and terminating the application of lubricant to the section of rail before an end of the train passes the section of rail so that the quantity of lubricant on the section of rail is reduced by wheels of a plurality of cars proximate the end of the train. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the sole accompanying drawing which is a schematic illustration of a train passing over a section of rail serviced by a wayside lubrication system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A wayside lubrication apparatus  10  is shown in  FIG. 1  as being installed along a rail  12  over which is passing a train  14  having two locomotives  16  and a plurality of load cars  18 . The locomotives  16  at the head of the train  14  are located at a first position  20  along the rail  12 , for example at the beginning of a curved section of the rail  12 . 
     The wayside lubrication apparatus  10  includes a lubricant dispensing apparatus  22  incorporating a pump  24  for supplying a lubricant  26  to rail  12  through applicator  28 . The lubricant  26  may be a petroleum or soybean based oil, a molybdenum or graphite grease or any of the specialty rail lubricants known in the art. The applicator may be a spray nozzle, mechanical wiper, dispenser tube outlet or other known mechanism. 
     The operation of lubricant dispensing apparatus  22  is controlled by a controller  30 , although less sophisticated systems also described herein may not require the control processes utilized in the system shown in the figure. Controller  30  may include a switch, relay, microprocessor, or other known form of process control device. In one embodiment, controller  30  includes machine-executable logic expressed in the form of software and/or firmware. Controller  30  functions to operate pump  24  in response to a lubrication signal  32  provided by a train head  4  sensor (S H )  34  located proximate first position  20  of rail  12 . Sensor  32  produces lubrication signal  32  in response to the presence of train  14  at first position  20  by sensing the weight of locomotive  16  or by other known method, such as optical, infrared and/or sonic technologies. 
     Lubricant dispensing apparatus  22  is located at a second position  36  along rail  12  that is separated from the first position  20  by a distance along rail  12  sufficient to prevent the lubricant from contacting drive wheels  38  of locomotives  16 . In this manner, the lubricant  26  applied by wayside lubrication apparatus  10  will function to reduce the friction between the rail  12  and the wheels  40  of the load cars  18 , but will not reduce the traction capability of the locomotive drive wheels  38 . The distance D between the first  20  and second  36  position along the rail  12  may be selected to span the length of the largest locomotive consist used on the particular rail line. 
     In certain applications it may not be possible to separate sensor  34  and applicator  28  by a distance D sufficient to prevent lubricant  26  from contacting the locomotive drive wheels  38 . For such applications, it may be desirable to include a timed delay between the generation of lubrication signal  32  and the actual start of the application of the lubricant  26  onto rail  12 . A timer  42  may be incorporated into controller  30  or provided as a discrete device for providing a time signal  44  to controller  30 . Logic executed by controller  30  provides that pump  24  is energized only after a predetermined time interval has elapsed after receipt of lubrication signal  32  by controller  30 . In this manner, lubricant dispensing apparatus  22  will operate to provide lubricant  26  to only the wheels  40  of the load cars  18  and not to the drive wheels  38  of locomotives  16 . The time interval of this embodiments functions as the equivalent to distance D described above. Furthermore, the time interval may be changed in response to other inputs received by controller  30 . For example, it is possible to detect the speed of the train  14  and to correlate the speed to the time delay required to achieve an effective distance D. As the speed of the train increases, the required time delay decreases. Furthermore, it is possible to detect the type and/or number of locomotives  16  included in train  14  and to correlate such information to a required effective distance D. As the size of the locomotive  16  and/or the number of locomotives  16  in the consist increase, the required time delay increases. 
     A time delay may also be implemented by the rime necessary to fill delivery tube  27  with lubricant. Delivery tube  27  may be empty of lubricant when pump  24  is first energized, and the internal volume of tube  27  will be filled before the lubricant begins to be expelled from applicator  28 . To ensure that delivery tube  27  is empty when pump  24  is first energized, a drain capability may be provided. 
     In a further embodiment, each axle of train  14  may function to pump a small quantity of lubricant through applicator  28 , either by the pumping action of the axle force on the rail or by the intermittent actuation of pump  24  in response to each axle passing a point on the rail  12 . In this manner, the total quantity of lubricant applied to the rail  12  as a result of the limited number of axles of the locomotive(s) will be insufficient to effectively lubricate the rail  12 . Only after a greater quantity of axles have passed over the point on the rail  12  will there be sufficient lubricant  26  to provide an effective degree of lubrication. 
     Time signal  44  may also be used to prevent the lubrication of rail  12  more often than is necessary to maintain a desired level of lubrication in the event of closely spaced trains  14 . Lubricant  26  applied to the rail  12  will lose its effectiveness due to a number of factors, including the time period since its application. Most lubricants  26  will flow away from the desired area of the rail  12  over time as a function of the viscosity of the lubricant  26 . Furthermore, many lubricants are formulated to be rapidly biodegradable in order to minimize their impact on the environment. Therefore, if a second train follows a first train  14  within a relatively short time period, no further lubrication of the rail  12  may be needed. Accordingly, controller  30  may be programmed with logic establishing a minimum time period between applications of lubricant  26  in order to conserve lubricant. 
     It may also be desirable to terminate the application of lubricant  26  prior to the time when all of the load cars  18  have passed the applicator  28 . The wiping/cleaning action of the wheels  40  of the load cars  46  at the rear of the train  14  can function to reduce the quantity of lubricant  26  remaining on the rail  12  after the train  14  has passed in order to prevent the lubricant  26  from adversely affecting the traction performance of any following locomotives. An end of train sensor (S E )  48  may be located at a third position  50  along rail  12  to produce a train end signal  52  responsive the end of train  14  passing third position  50 . Train end signal  52  is processed by controller  30  to terminate the application of lubricant  26  before a predetermined number of rear load cars  46  pass the location of the applicator  28 . This process may include consideration of the speed of the train  14  and/or variables affecting the cleaning efficiency of the rear load cars  46 , such as temperature for example. 
     Environmental conditions such as temperature, rail, snow, fog and wind may effect the performance of the lubricant  26  on the rail  12 . It may be desirable to include as part of wayside lubrication apparatus  10  an environmental sensor such as moisture sensor (S M )  54  for detecting the presence of moisture on rail  12 . Because water is a lubricant, it may be unnecessary to provide additional lubricant  26  when the rail  12  is wet from rain, snow or fog. A moisture signal  56  responsive to such environmental conditions may be used by controller  30  to prevent the application of lubricant  26  by the lubricant dispensing apparatus  22  in response to a predetermined environmental condition. 
     It may also be advantageous to provide for human intervention to prevent the application of lubricant  26  in response to the lubrication signal  32 . For example, in a system not having a moisture sensor  54 , it may be desirable to provide an operator on-board the train  14  with the capability of bypassing the operation of the lubricant dispensing apparatus  22  during wet operating conditions. One such bypass device  58  includes a wireless communication system transmitter  60  responsive to an operator action on-board locomotive  16  and an associated wireless communication system receiver  62  for producing a bypass signal  64  responsive to the operator action. Controller  30  may be programmed with instructions for bypassing the operation of pump  24  in spite of the presence of lubrication signal  32  in the presence of bypass signal  64 . Wireless communication system receiver  62  may further be responsive to a wireless signal initiated by a central control facility or weather measuring facility (not shown) positioned at a remote location. The bypass device  58  may alternatively include a hard-wired communication device for receiving a bypass signal  64  from a remote location. 
     Pump  24  may draw lubricant  26  directly from a large reservoir  66 , or as illustrated in the figure, from a smaller lubricant container  68 . Lubricant  26  is provided to the container  68  by gravity or preferably via forced flow. In order to limit the total volume of lubricant  26  that can be applied to rail  12  over a short period of time, a refilling device  70  is provided for adding lubricant  26  to the lubricant container  68  at no more than a predetermined rate. The refilling device  70  may include a controlled flow pump (not shown), a valve  72  controlled by controller  30 , and/or an orifice  74  located in a lubricant container refilling line  76 . Any one or combination of such devices function to limit the accumulation of lubricant  26  within container  68 , thereby limiting the amount of lubricant  26  available for delivery to applicator  28  by pump  24 . After a sufficiently long time period has elapsed since the previous lubricant application, lubricant container  68  will be completely full and a full charge of lubricant  26  can be delivered to rail  12  in response to lubrication signal  32 . If the time period elapsed since the previous lubricant application is not sufficiently long, the amount of lubricant applied to rail  12  by lubricant dispensing apparatus  22  in response to the presence of a second train  14  will be correspondingly reduced from a full charge amount. 
     While the preferred embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those of skill in the art without departing from the invention herein. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.