Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Railway vehicle
Reexamination Certificate
2000-09-08
2003-02-25
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Railway vehicle
C701S050000, C701S207000, C701S213000, C701S214000, C246S127000, C105S311100, C221S092000, C222S482000, C222S129000
Reexamination Certificate
active
06526339
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to logistics and, more particularly, to a GPS based system for spreading ballast along railroad tracks for track maintenance.
BACKGROUND OF THE INVENTION
Conventional railroads in the United States and elsewhere are typically formed by a compacted sub-grade, a bed of gravel ballast, wooden cross-ties positioned upon and within the ballast, and parallel steel rails secured to the ties. Variations of construction occur at road and bridge crossings and in other circumstances. The ballast beneath and between the ties stabilizes the positions of the ties, keeps the rails level, and provides some cushioning of the composite structure for loads imposed by rail traffic. Vibrations from the movement of tracked vehicles over the rails and weathering from wind, rain, ice, and freeze and thaw cycles can all contribute to dislodging of some of the ballast over time. Thus, in addition to other maintenance activities, it is necessary to replace ballast periodically to maintain the integrity and safety of railroads.
Conventionally, ballast is spread using specially configured ballast hopper cars which include a hopper structure holding a quantity of ballast, a ballast chute communicating with the hopper, and a motorized ballast discharge door in the chute. The door can be controlled to selectively open or close to control the discharge of ballast. In some designs, the discharge door can be controlled to open outboard toward the outside of the rails, to close, or to open inboard toward the inside between the rails. Typical ballast hopper cars have a front hopper and a rear hopper, and each hopper has two transversely spaced doors, one to the left and one to the right. Thus, each hopper door can be controlled to discharge ballast outside the rails on the left and/or the right or between the rails. A typical configuration of a ballast hopper car is described in more detail in U.S. Pat. No. 5,657,700, which is incorporated herein by reference.
In general, ballast spreading has been controlled manually in cooperation with spotters who walk alongside the moving ballast cars to open or close the ballast doors as necessary. A more recent ballast spreading control technique is by the use of a radio linked controller carried by an operator who walks alongside the moving ballast cars. Both conventional control methods are so slow as to disrupt normal traffic on the railroad section being maintained, thereby causing delays in deliveries and loss of income.
Copending application, Ser. No. 09/285,290, generally discloses methods for spreading railroad ballast with location control based on data received from the global positioning system or GPS. The GPS system, also referred to as NAVSTAR, is a “constellation” of satellites traveling in orbits which distribute them around the earth, transmitting location and time signals. As originally designed, a GPS receiver, receiving signals from at least four satellites, was able to process the signals and triangulate position coordinates accurate to about ten to twenty meters. Current generations of commercially available GPS receivers, using differential GPS techniques, are able to achieve accuracies in the range of one to five meters. Such accuracy is adequate for depositing ballast where desired and inhibiting the deposit of ballast where it is not desired. Additional information regarding the development of GPS technologies can be obtained from U.S. Pat. Nos. 4,445,118 and U.S. Pat. No. 5,323,322 which are incorporated herein by reference. Development of the GPS system referred to herein was sponsored by the United States government. However, satellite based positioning systems developed or operated by other nations are also known.
Because railroad companies typically maintain hundreds or thousands of miles of track on a recurring schedule, the ballast replacement component of track maintenance alone can be a major undertaking in terms of equipment, materials, traffic control, labor, and management. Knowing the ballast capacity of the hoppers of a ballast car and the flow rate through the ballast doors, it would be possible to provide each ballast car with a GPS receiver, to program an individual on-car computer with a set of spread coordinates and ballast distribution parameters, and to control the flow of ballast in a spread zone in relation to measured or computed car speed. However, such an approach would be expensive in terms of GPS receivers and control computers and would be extremely laborious for a large project. Additionally, coordination and record keeping would be complicated by such a piecemeal approach.
SUMMARY OF THE INVENTION
The present invention provides methods and apparatus for controlled spreading of ballast on a railroad on a large scale basis using multiple ballast hopper cars spreading simultaneously, at times. The system of the present invention uses location coordinates provided by a differential GPS receiver to coordinate the opening of ballast doors to spread controlled quantities of ballast on sections where ballast is desired and to inhibit spreading ballast where not desired or not needed. The system allows the ballast train to spread ballast mostly at a high enough speed that normal traffic on the railroad on which it is operating is only minimally affected by its presence.
In practice of the present invention, a ballast train includes one or more locomotives, a control car, and a plurality of ballast hopper cars, such as fifty hopper cars. Each hopper car has two hoppers, left and right ballast chutes for each hopper, a ballast door for each chute, and a hydraulic actuator for each door. The actuator can be controlled to open its associated door to an inboard direction, between the rails, or to an outboard direction, outside of the rails. Each hopper can hold a known load of a particular type of ballast, and the average flow rate of a given type of ballast through a ballast door is also known. Each hopper car has car logic circuitry, referred to as a car control unit or CCU and also as a “neuron”, which controls operation of the hydraulic actuators and which monitors certain functions on the car.
The CCU's communicate with a central control or head end controller (HEC) through a network including a bus referred at places herein as a “wireline”. The bus extends from the HEC through the CCU of each car, interrupted by a set of a front and a rear communication relay in each CCU, which is controlled by the local CCU. The communication relays can be used to determine the orientation of each car by a procedure which will be detailed below. The HEC may be a general purpose type of computer, such as a laptop, and has a differential GPS receiver interfaced thereto to provide geographic coordinates. The GPS receiver includes a GPS antenna, the location of which forms a reference location or datum for the train. The relative location of each ballast door on each hopper car of the train will be determined in relation to the reference location. Ordinarily, the ballast train will use a plurality of virtually identical hopper cars with known distances between the ballast doors on a given car and between the ballast door of one car and the next adjacent car.
In order to control the spreading of ballast on a length of track, it is necessary to obtain the geographic coordinates of the track. This is most conveniently accomplished by a survey run on the track using a road vehicle equipped with flanged wheels for traveling on rails, such as a Hy-Rail vehicle (trademark of Harsco Technologies Corporation). The track survey vehicle is equipped with a differential GPS receiver and a computer, which may be the HEC computer, and track survey software. As the survey vehicle travels along the track, the survey crew, which may be or include a “roadmaster”, marks spread zones where ballast is to be spread and non-spread zones, such as bridges, road crossings, and the like, where ballast is not to be spread. In some circumstances, it may be necessary for the survey crew to stop the survey veh
Bedingfield Stephen L.
Bounds Ivan Eugene
Harris Patrick R.
Herzog Stanley M.
Laughlin Daniel B.
Broadhead Brian J
Herzog Contracting Corp.
Louis-Jacques Jacques H.
Shook Hardy & Bacon L.L.P.
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