Locomotives Patents (Class 105/26.05)
  • Patent number: 7500436
    Abstract: A locomotive (10) is operable in two or more distinct configurations, with the change in configuration being response to a configuration input signal (35). A locomotive configuration is represented by the set of end use device control signals (13) that are generated by the locomotive control systems (22) in response to the respective set of operational input values (27). For a given set of operational input values, a first set of end use device control signals is generated when a configuration input has a first value, and a second set of end use device control signals is generated when a configuration input has a second value. The configuration input variable is responsive to an emission profile associated with the locomotive location. A value of a locomotive emission parameter corresponding to the emission profile is monitored and saved in a storage device (e.g., 104).
    Type: Grant
    Filed: May 25, 2005
    Date of Patent: March 10, 2009
    Assignee: General Electric Company
    Inventors: Ajith Kuttannair Kumar, Steven Matthew Pelkowski, Mark Bradshaw Kraeling, Glen Paul Peltonen, James Kiss, Daniel Malachi Ballesty, Wolfgang Daum, Bradley Charles Hendrickson, Gerald James Hess, Jr., Glenn Robert Shaffer, Daniel F. Wolf, Leonard Michael Hill, Steven Andrew Kellner
  • Publication number: 20090038500
    Abstract: A method for testing the health of locomotive battery blocks includes coupling a load to a first and a second battery block, the first and second battery blocks are coupled in series, activating a contactor coupled between the first and second battery blocks and the load to channel electrical energy from the load to the first and second battery blocks, and determining a voltage of the first and second battery blocks to determine the health of the locomotive battery blocks. A portable battery block health tester and a locomotive including a battery block health tester are also described herein.
    Type: Application
    Filed: August 6, 2007
    Publication date: February 12, 2009
    Inventors: Ramesh Bhardwaj, Ajith Kuttannair Kumar
  • Patent number: 7444944
    Abstract: A hybrid power locomotive system has a plurality of combustion engines for driving a plurality of electric power generators that supply electric power to at least one traction battery. The battery is connected to supply power to a plurality of electric traction motors coupled in driving relationship to respective ones of a plurality of wheel-axle sets of the locomotive. At least one traction motor drive is connected for controlling power to the electric traction motors. An electric power controller is arranged for coupling electric power from the power generators to the battery and senses the available energy in the battery and the power demand from the traction drives for activating selected ones of the plurality of combustion engines for charging the battery.
    Type: Grant
    Filed: June 15, 2005
    Date of Patent: November 4, 2008
    Assignee: General Electric Company
    Inventors: Ajith Kuttannair Kumar, Robert D. King, Chi-Houng Eddie Lu, Leonard Michael Hill
  • Publication number: 20080223250
    Abstract: A head end power system carried on a locomotive for a passenger train set that captures and stores excess electrical energy generated during dynamic braking of the locomotive. This excess electrical energy is converted to head end power for use on attached passenger railcars. Because passenger trains activate dynamic braking frequently, sufficient dynamic braking energy can be captured to supply a substantially continuous demand for head end power. In the event that the amount of captured energy is insufficient to meet demand, the head end power system may supplement the captured energy with energy generated by the primary power source on the locomotive.
    Type: Application
    Filed: March 13, 2007
    Publication date: September 18, 2008
    Inventor: Eric C. Bachman
  • Publication number: 20080202376
    Abstract: A railroad locomotive includes a naturally aspirated reciprocating internal combustion engine driving a traction generator. A speed control system and load regulator provide an output signal which is operated upon and modified by a controller in response to the barometric pressure at which the locomotive is being operated.
    Type: Application
    Filed: February 23, 2007
    Publication date: August 28, 2008
    Applicant: GENERAL ELECTRIC COMPANY
    Inventors: Mikhail Meltser, Bryan Thomas Jett, Neil Xavier Blythe, Ronald Bauerle, Ajith Kumar
  • Patent number: 7401558
    Abstract: A diesel-electric locomotive includes a diesel engine which is connected to a generator. A cable originates from the generator to supply electrical power to a drive unit. An additional cable originates from the generator to supply electrical power to secondary appliances. The additional cable further includes a transformer therein.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: July 22, 2008
    Assignee: Siemens Aktiengesellschaft
    Inventor: Ulrich Foesel
  • Patent number: 7392749
    Abstract: A propulsion skid module useful for refurbishing locomotives is taught. In one embodiment, the propulsion skid module includes a skid base serving as a support for an engine; the skid base including at least two support members extending substantially the length of the module and at least one panel spanning the two support members; with the module further comprising an engine; a blower for delivery of air under pressure, a control device compartment, an auxiliary cab including power connectors, and an air compressor secured onto the skid base; and an air plenum defined in the base. Methods for refurbishing a locomotive are also taught.
    Type: Grant
    Filed: April 28, 2005
    Date of Patent: July 1, 2008
    Assignee: General Electric Company
    Inventors: John B. Bendig, Alexander G. Grigorian, Joseph J. McQuiston
  • Publication number: 20080105157
    Abstract: A safety system for a walkway of a locomotive. The safety system includes an operator cabin adjacent to a front end of the locomotive, and a walkway extending from the operator cabin along a first side of the locomotive to facilitate a locomotive operator performing regular maintenance. More particularly, the safety system includes a resistive grid exhaust in a sidewall of the first side of the locomotive for directing hot air along a path from a resistive grid within the sidewall to external the locomotive during a self-load mode of the locomotive. A barrier bar is positioned adjacent to the base of the resistive grid exhaust, and is extendable to an extended position over the walkway during the self-load mode to prevent the operator from walking into the path of the hot air from the resistive grid exhaust.
    Type: Application
    Filed: November 8, 2006
    Publication date: May 8, 2008
    Inventors: Carl S. Iszkula, Leroy Learn, Soban Jalil
  • Publication number: 20080053331
    Abstract: A train is connected to provide wired distribution power (WDP) using at least one standard locomotive consist. The train includes a first locomotive separated from a second locomotive by a plurality of cars; and a communication train line connected to the locomotive and cars and extending through the train. Each of the locomotives has a propulsion system, a propulsion controller to control the propulsion system in response to one of operator propulsion signal and multi-unit (MU) propulsion signal, and a MU communication line and connector for communicating control signals, including the MU propulsion signal, with an adjacent locomotive. At least the first locomotive is connected to the communication train line of an adjacent car by the multi-unit connector of the first locomotive to one of receive and transmit the MU propulsion signals via the communication train line.
    Type: Application
    Filed: August 29, 2006
    Publication date: March 6, 2008
    Inventors: Jon M. Marra, Bryan M. McLaughlin, James R. Truglio, Dale R. Stevens
  • Patent number: 7302895
    Abstract: A locomotive (10) is operable in two or more distinct configurations, with the change in configuration being response to a configuration input signal (35). A locomotive configuration is represented by the set of end use device control signals (13) that are generated by the locomotive control systems (22) in response to the respective set of operational input values (27). For a given set of operational input values, a first set of end use device control signals is generated when a configuration input has a first value, and a second set of end use device control signals is generated when a configuration input has a second value. The configuration input variable may be responsive to the locomotive location, a wayside device signal, an operator action or the health of the locomotive, for example. Locomotive configuration changes may include peak horsepower rating, number of engine cylinders fueled, number of throttle notch settings, adhesion limits, mission priorities or emission profile, for example.
    Type: Grant
    Filed: December 9, 2004
    Date of Patent: December 4, 2007
    Assignee: General Electric Company
    Inventors: Ajith Kumar, Glenn Shaffer, Wolfgang Daum, Leonard Hill, James Glen Corry, Daniel Wolf, Steven Andrew Kellner
  • Patent number: 7190133
    Abstract: A hybrid propulsion system. The system comprises one or more hybrid propulsion traction drives having an electric motor operable to produce mechanical power for propulsion. A hybrid propulsion traction drive is operable to receive power from an on-board power generation system. The electric motor is operable to receive power from an energy storage unit and operable to supply power to the energy storage unit. The energy storage unit may be coupled to the electric motor via a switch.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: March 13, 2007
    Assignee: General Electric Company
    Inventors: Robert Dean King, Dongwoo Song, Lembit Salasoo, Ajith Kuttannair Kumar
  • Patent number: 7124691
    Abstract: The present invention is directed to a locomotive comprising energy storage units, such as batteries, a prime energy source, such as a diesel engine, and an energy conversion device, such as a generator. The locomotive comprises one or more of the following features: a separate chopper circuit for each traction motor; energy storage units that can be switched from parallel to series electrical connections, an fluid-activated anti-lock brake system, a controller operable to control separately and independently each axle/traction motor, and a controller operable to control automatically a speed of the locomotive. The present invention includes an integrated system for monitoring, controlling and optimizing an electrically powered locomotive using a combination of sensors and software to provide feedback that optimizes power train efficiency and individual drive axle performance for a locomotive that utilizes one of several possible electrical energy storage systems to provide the tractive power.
    Type: Grant
    Filed: August 26, 2003
    Date of Patent: October 24, 2006
    Assignee: Railpower Technologies Corp.
    Inventors: Frank Wegner Donnelly, Brian Gulayets Iwan, John David Watson, David Herman Swan
  • Patent number: 7064507
    Abstract: The present invention is directed to the termination of the occurrence of wheel slip/skid and prediction and prevention of the onset of wheel slip/skid in a locomotive. In one configuration, a lookup table of adhesion factors is used to predict the occurrence of wheel slip/skid.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: June 20, 2006
    Assignee: Railpower Technologies Corp.
    Inventors: Frank Wegner Donnelly, John David Watson
  • Patent number: 7045981
    Abstract: A high-altitude railroad locomotive adapted for more reliable operation at high altitudes, wherein the high-altitude railroad locomotive includes a semiconductor electric power control component, and wherein due to the high altitude the locomotive would be exposed to high levels of cosmic radiation tending to damage the semiconductor electric power control component is provided. The high-altitude locomotive includes electric power generation equipment, a plurality of traction motors mechanically connected to wheels supporting the high altitude locomotive and an electric power transmission system for transmitting electrical power from the electric power generation equipment to the plurality of traction motors.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: May 16, 2006
    Assignee: General Electric Company
    Inventors: Mark Louis Nicolussi, Paul Robert Hokanson, Ajith Kuttannair Kumar
  • Patent number: 6886472
    Abstract: In a railroad locomotive having a plurality of systems which collectively are used for locomotive operations, a method of self-healing a system of the plurality of systems comprising monitoring operational conditions of the system, detecting at least one of a pending and a current failure, determining a self-healing procedure to correct the failure, and applying the self-healing procedure comprising at least one of a safe mode technique, a redundancy technique, and an automatic configuration technique.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: May 3, 2005
    Inventors: Vinay Bhaskar Jammu, Raj Mohan Bharadwaj
  • Patent number: 6828746
    Abstract: A method and system for detecting the occurrence of an actual locked condition in a locomotive system having a locomotive operating in an isolated mode of operation. The locomotive has a plurality of AC traction motors for propelling the locomotive system during normal operations. The AC motors are reconfigurable to operate as AC generators and are connected to a common DC bus. When a potential locked condition in a first motor is detected, the DC bus is energized with an initial voltage using an alternate source of power. The DC bus voltage is regulated with a second motor by reconfiguring the second motor to operate as a generator. The torque produced by the first motor is then measured at a plurality of levels of electromagnetic flux in the first motor. Based on the measured torque, it is determined whether the potential locked condition is an actual locked condition.
    Type: Grant
    Filed: December 12, 2002
    Date of Patent: December 7, 2004
    Assignee: General Electric Company
    Inventor: Ajith Kuttannair Kumar
  • Publication number: 20040216636
    Abstract: A hybrid transport vehicle, which needs an overhead wire and/or a railway and has a plurality of kinds of energy supply systems and/or driving apparatuses, is provided with a condition detection device for detecting an energy supply condition of the energy supply systems and/or an operation condition of the driving apparatuses, and an informing device for informing the energy supply condition and/or the operation condition, detected by the condition detection device.
    Type: Application
    Filed: March 2, 2004
    Publication date: November 4, 2004
    Applicants: Hitachi, Ltd., Hitachi Mito Engineering Co., Ltd.
    Inventors: Akihiko Emori, Eiichi Toyota, Masato Suzuki, Motomi Shimada, Tsutomu Miyauchi
  • Publication number: 20040149159
    Abstract: A diesel-electric locomotive includes an assembly including a diesel engine and a generator, to which a drive unit can be connected. There is provision for the assembly to be replaceable as a module. For this purpose, it is arranged, for example, in a replaceable container.
    Type: Application
    Filed: April 10, 2003
    Publication date: August 5, 2004
    Inventors: Ulrich Foesel, Christian Gritsch, Heinz Hofmann, Gyoergy Papp
  • Patent number: 6725782
    Abstract: A railroad test vehicle extending in a longitudinal direction comprises a measurement axle comprising two flanged wheels rotatable about a measuring axis extending transversely to the longitudinal direction and adapted to run on two track rails. A cross member extends transversely to the longitudinal direction, is vertically spaced from an underside of the vehicle and is affixed thereto. The connection between the measurement axle and the cross member comprises two trunnions transversely spaced from each other and mounted on the cross member, each trunnion defining a clearance with the cross member sufficient to enable the trunnion to be freely tilted to either side of the vehicle about an axis extending in the longitudinal direction, a support frame mounted on each trunnion for pivoting freely about an axis extending perpendicularly to the longitudinal direction, and two pairs of linkages, the pairs being transversely spaced from each other by the same distance as the transversely spaced trunnions.
    Type: Grant
    Filed: March 24, 2003
    Date of Patent: April 27, 2004
    Assignees: Franz Plasser Bahnbaumaschinen-Industriegesellschaft m.b.H, Ensco, Inc.
    Inventors: Jeffrey A. Bloom, Gary A. Carr, Georg Seyrlehner, Ta-Lun Yang, Günther W. Oberlechner
  • Publication number: 20030233959
    Abstract: A hybrid energy railway vehicle system having a traction motor with a dynamic braking mode of operation for dynamically braking the traction motor and for generating dynamic braking electrical energy and an electrical energy storage system that is in electrical communication with the traction motor and that stores dynamic braking electrical energy generated by the traction motor. The system also has a hybrid energy railway vehicle with a plurality of wheels wherein the traction motor has a motoring mode of operation for driving one of the wheels in response to electrical input energy. A converter selectively provides stored electrical energy from the energy storage system to the traction motor as electrical input energy for driving one or more of wheels.
    Type: Application
    Filed: May 9, 2003
    Publication date: December 25, 2003
    Applicant: General Electric Company
    Inventor: Ajith Kuttannair Kumar
  • Patent number: 6612245
    Abstract: An energy tender vehicle for use in connection with a hybrid energy locomotive system having an energy storage and regeneration system. The energy storage and regeneration system captures dynamic braking energy, excess motor energy, and externally supplied energy in one or more energy storage subsystems, including a flywheel, a battery, an ultra-capacitor, or a combination of such subsystems. In one form, the energy storage and regeneration system is located in the energy tender vehicle. The energy tender vehicle is optionally equipped with traction motors. In one form, the energy tender is configured to operate without any power connections to the locomotive. An energy management system is responsive to power storage and power transfer parameters, including data indicative of present and future track profile information, to determine present and future electrical energy storage and supply requirements. The energy management system controls the storage and regeneration of energy accordingly.
    Type: Grant
    Filed: December 26, 2001
    Date of Patent: September 2, 2003
    Assignees: General Electric Company, Carl Rowold
    Inventors: Ajith Kuttannair Kumar, Admir Mesalic
  • Publication number: 20020174796
    Abstract: An energy tender vehicle for use in connection with a hybrid energy locomotive system having an energy storage and regeneration system. The energy storage and regeneration system captures dynamic braking energy, excess motor energy, and externally supplied energy in one or more energy storage subsystems, including a flywheel, a battery, an ultra-capacitor, or a combination of such subsystems. In one form, the energy storage and regeneration system is located in the energy tender vehicle. The energy tender vehicle is optionally equipped with traction motors. In one form, the energy tender is configured to operate without any power connections to the locomotive. An energy management system is responsive to power storage and power transfer parameters, including data indicative of present and future track profile information, to determine present and future electrical energy storage and supply requirements. The energy management system controls the storage and regeneration of energy accordingly.
    Type: Application
    Filed: December 26, 2001
    Publication date: November 28, 2002
    Applicant: General Electric Company
    Inventors: Ajith Kuttannair Kumar, Admir Mesalic
  • Publication number: 20020174797
    Abstract: A hybrid energy locomotive system having an energy storage and regeneration system. In one form, the system can be retrofitted into existing locomotives or installed as original equipment. The energy storage and regeneration system captures dynamic braking energy, excess motor energy, and externally supplied energy, and stores the energy in one or more energy storage subsystems, including a flywheel, a battery, an ultra-capacitor, or a combination of such subsystems. The energy storage and regeneration system can be located in a separate energy tender vehicle. The separate energy tender vehicle is optionally equipped with traction motors. An energy management system is responsive to power storage and power transfer parameters, including data indicative of present and future track profile information, to determine present and future electrical energy storage and supply requirements. The energy management system controls the storage and regeneration of energy accordingly.
    Type: Application
    Filed: December 26, 2001
    Publication date: November 28, 2002
    Applicant: General Electric Company
    Inventor: Ajith Kuttannair Kumar
  • Patent number: 6397759
    Abstract: A locomotive is described including a frame having a wall with a roof and floor defining an enclosed space thereon. A turbine engine is disposed within the enclosed space. An air inlet is provided to permit ingress of air into the enclosed space for ingestion by the turbine and for circulation around the turbine to cool the turbine. A first silencer is disposed between the air inlet and the turbine to minimize noise generated by the turbine. An exhaust duct, for connection to the exhaust outlet of the turbine, is also provided to permit egress of exhaust gases generated by the turbine from the enclosed space. In addition, a second silencer, connected to the exhaust duct, is provided to minimize noise generated by the turbine. Finally, at least one of the wall, roof, and floor of the enclosed space incorporate noise dampening materials to minimize noise generated by the turbine. An enclosure assembly for a turbine is also disclosed.
    Type: Grant
    Filed: July 28, 2000
    Date of Patent: June 4, 2002
    Assignee: Bombardier Inc.
    Inventors: Daniel Hubert, Bernard Raynauld, Jean Desrosiers
  • Patent number: 6360672
    Abstract: A protective member positioned at the rear of the operator cab of a locomotive. The protective member provides impact protection for a passenger in the locomotive in the event of an impact between the rear panel of the locomotive and a foreign object during long hood lead (reverse) operation. The protective member may include a vertical member disposed under the outer sheet material at a rear corner of the operator cab as well as members surrounding the rear window opening. The protective member may be formed of rectangular steel tubing and is anchored directly or indirectly to the platform of the locomotive.
    Type: Grant
    Filed: October 12, 2000
    Date of Patent: March 26, 2002
    Assignee: General Electric Company
    Inventor: Gail Leroy Detar
  • Publication number: 20020035417
    Abstract: A system (100) and method for expediting the repair of a locomotive (102) having sustained damage (104) as a result of a collision. A library of as-built parts information (114) is manipulated to define a plurality of repair kits (110) each containing all of the parts necessary to repair the damage expected from a predefined collision event. A particular repair kit may be selected by a user in response to an actual collision to obtain a listing of the parts (308), a cost estimate (318) and a delivery forecast (320). All of the necessary parts may then be ordered as a unit and delivered to a repair location (106) in a single shipment, thereby minimizing the chance of missing or misplaced parts. The system may be accessed via an information network, and the selection of specific repair kit may be facilitated by the use of a graphical user interface to point-and-click on the damaged regions of the locomotive.
    Type: Application
    Filed: April 20, 2001
    Publication date: March 21, 2002
    Inventors: Brian Lee Badger, Raymond Paul Stempka, Jeffery M. Smith, Michael Allan Lubak, Kathleen M. Vash
  • Patent number: 6336409
    Abstract: The rake is made up of at least two vehicles with two levels and includes on-board equipment items including at least one traction motor power supply unit, motive power supply units, auxiliary power supply units and a device adapted to be connected to a power supply network. At least one vehicle includes at least one motor bogie and at least one carrying bogie; at least one carrying bogie of the rake is associated with at least one of said on-board equipment items disposed approximately over it; the ratio between the respective motive power factors of any two groups of two vehicles of the rake is not less than ⅓ and not more than 3. The rake is for carrying passengers.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: January 8, 2002
    Assignee: Alstom
    Inventor: Guy Devulder
  • Patent number: 6327980
    Abstract: Automatic control of the temperature of the inlet air being supplied to the engine (12) of a locomotive (10) in order to optimize the performance of the engine (12) under a variety of ambient air temperatures and pressures. One or more valves (38) is utilized to control the flow of warm air from the engine compartment (14) into the air inlet path (20). The position of valve (38) is controlled by controller (42) in response to at least one of an ambient air temperature signal TA, an ambient atmospheric pressure signal PA, and an inlet air temperature signal TI. The temperature of the air flowing through the warm air flow path 28 may be controlled by selecting from among a plurality of possible inlets (30, 32, 50). By varying the volume and temperature of the air flowing through the warm air flow path (28), the temperature and density of the air supplied at the engine inlet (18) may be moderated across a broad range of ambient air temperatures and pressures.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: December 11, 2001
    Assignee: General Electric Company
    Inventors: Gong Chen, Gregory A. Marsh, Ronald H. Till, Peter L. Valentine
  • Patent number: 6308639
    Abstract: Prior battery-powered electric locomotives have used multiple diesel engines to charge the batteries and have not been commercially accepted. The present invention provides a yard switcher which combines battery storage with a gas microturbine generator to provide an effective fuel-efficient and environmentally friendly locomotive. locomotive.
    Type: Grant
    Filed: April 26, 2000
    Date of Patent: October 30, 2001
    Assignee: Railpower Technologies Corp.
    Inventors: Frank Wegner Donnelly, Gerard Henry Koldyk
  • Patent number: 6267062
    Abstract: The two axle locomotive of this invention includes a diesel engine directly coupled to a generator for generating power to a single electrical traction motor. Preferably, the drive motor is an AC traction motor which drives both axles of the locomotive using a single drive shaft assembly with a drive shaft affixed to an armature of the AC traction motor. Power to the AC traction motor is controlled by using a variable frequency alternating current control system. Auxiliary equipment power is also provided by the AC generator. In addition, by reversing the current in the AC traction motor the motor becomes an AC braking motor. Changes in the traction ability of each axle resulting from weight transfer between the two axles is automatically compensated for by the single drive shaft assembly. The suspension system includes a locomotive frame supported by the pair of axles using elastomeric springs, which also provides dynamic damping to limit the motion of the locomotive.
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: July 31, 2001
    Inventor: Hugh B. Hamilton, Jr.
  • Patent number: 6186074
    Abstract: The present invention provides a drive assembly for a model toy train which connects a single drive shaft from an electric motor to a pair of discrete truck assemblies. The drive shaft drives a plurality of pinions which in turn drive a pair of worm shafts which extend toward the truck assemblies. A pair of worm wheel shafts are driven by the worm shafts to drive the wheels on the truck assemblies. A saddle and bearing combination rotationally connects the model toy train to the truck assemblies allowing the truck assemblies to freely rotate.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: February 13, 2001
    Assignee: Lionel Trains, Inc.
    Inventors: Robert A. Grubba, Caleb Sullivan, Kevin B. Chlebek, Jeffery A. Price
  • Patent number: 6182577
    Abstract: This invention is a transportation system and method of transport the provides a way for transport of vehicles in which the vehicles are loaded onto self-propelled pallets that are coupled to self-propelled apparatus that is in turn coupled to a fixed and predetermined guide.
    Type: Grant
    Filed: May 28, 1998
    Date of Patent: February 6, 2001
    Inventor: Calvin Billings
  • Patent number: H1961
    Abstract: A universal directional reference for trailing locomotives and railroad cars employs a two wire mating connector for each end of the car or locomotive, each wire having a male contact at one end and a female contact at the opposite end and in a sense opposite to the other wire. A positive polarity established on one conductor having its male contact at the leading end of the controlling locomotive causes the same polarity to appear on the female contact at the rear end of said locomotive which is connected to the male contact of the next car or locomotive thereby sustaining the pattern throughout the train. Reverse orientation of any trailing unit automatically swaps the internal polarity of its trainline wires to compensate for the otherwise reverse direction of travel.
    Type: Grant
    Filed: April 5, 1999
    Date of Patent: June 5, 2001
    Assignee: Norfolk Southern Corporation
    Inventor: Robert S. Runyon