Patent Application
20060163004
This invention concerns a method and apparatus for applying lubricant to railroad rails. Rail lubrication on curves has been considered important for a long time, primarily for the purpose of reducing wear on wheels and rails. Traditionally, lubricating devices in railroad yards used long bars mounted on the gage side of the rail. Grease oozes out of small holes in the bar in response to the pressure of a passing train, and is picked up by the flanges of wheels and spread over the rail gage corner. These grease lubricators are difficult to control, leading to excessive grease being applied and accumulated near the applicator. It is messy, manpower intensive, hazardous to track crews, and expensive to maintain. In spite of such lubrication, high lateral forces continue to develop on the rail. This produces significant damage to track components such as spikes, ties, tie plates, ballast and the overall structure of the track.
A new approach called top-of-rail lubrication was introduced by Kumar in the early 1990s. See U.S. Pat. Nos. 5,477,941 and 5,896,947. In this approach, a lubrication system mounted on the last locomotive consistently applied lubricant or friction modifier on top of the rail as the train moved forward. This approach has been very beneficial, and today the railroad industry generally utilizes the top-of-rail method of lubrication. Since this system is installed on board a locomotive, it falls under the authority of the mechanical department in a railroad.
The engineering department of a railroad also needs a system for top-of-rail lubrication on curves. Recently, two different systems have been developed for achieving this. One system follows the approach similar to gage side grease lubricators. In this approach a long bar is installed on the field side and top of the rail. When wheels pass by, the pressure causes the lubricant to ooze out of the strip to be spread on the rail. This is not effective because it does not provide lubrication where it is needed most, particularly on the low rail in a curve. Also, the lubricant is not carried along the track for a sufficient distance.
There is a second approach called the wayside wheel lubricator which is currently at work in many railroad yards. This is shown in Kumar, U.S. Pat. No. 6,585,085, assigned to Tranergy Corporation. In this method, lubricant is applied through a nozzle to the wheels of approaching cars in a yard which move at relatively slow speeds (10 miles per hour or less). While this method is effective in railroad yards, for cars traveling at higher speeds (40 to 70 miles per hour) the lubricant application jet will have difficulty accurately hitting fast approaching wheels. There is therefore a great need for a ground-based, top-of-rail lubrication system which lubricates the contact area of the rail using an optimum amount of lubricant on the optimum area of the railhead.
To solve the above problems, this invention is directed to a method and apparatus for dispensing lubricant on at least one railroad rail. This invention offers a way to lubricate the contact area of the rail with proper and accurately controlled lubrication on the optimum area of the railhead. One or more nozzles are mounted in a block or strip, which is mounted on the rail gage side. The nozzles are preferably located below the railhead in order to stay clear of passing wheel flanges. The jets of lubricant fluid from the nozzles are aimed in such a way that the fluid exits the nozzle upwards and towards the rail and then falls on the rail. This requires the jet to be quite close to the railhead and aimed at an angle up and into the rail. As the jet exits the nozzle orifice, it grazes the edge of the rail which disperses the jet and creates a generally vertical curtain or sheet of lubricant. The curtain then falls onto a significant length of the rail. One or more such jets are fired by the nozzle holder simultaneously on the contact area of the rail in different directions from the applicator such that they fall on the railhead and gage corner. A correct distribution of fluid is thus applied to the contact area of the rail on different parts of the railhead, including the gage corner of the rail. As the wheels roll on this lubricated railhead, the fluid is picked up by the wheels and spread on the wheel tread and flange, as well as on the rail. The shots of fluid are fired on the rail when the wheel is at a reasonable distance (2 to 20 feet, or more) from the nozzle. Two sensors, one on each side of the nozzle holder, detect the presence of approaching wheels from either direction and cause the jet to be ejected when the wheels are absent from the target zone to be wetted with lubricant. The wheel detecting sensors are also preferably mounted on the gage side of the rail.
This method and apparatus for lubricating the contact area of the rail can be distinguished from the above-mentioned wayside lubricator of Kumar U.S. Pat. No. 6,585,085. The wayside lubricator aims a jet of lubricant directly at the wheels. With this aiming even if the timing were altered to avoid hitting a wheel, the wayside lubricator would still not lubricate the rail in the manner of the present invention. In fact, if a jet in the wayside lubricator were fired between passing wheels, the jet would shoot directly over the rail and land in between the rails or on the field side of the opposite rail, or the jet would hit the undercarriage of a passing car.
An alternate method of placing the nozzle blocks or strip on the field side is also discussed. The fluid jets rise up and towards the rail and then fall on the contact area. Top-of-rail lubrication can be done by this method when it is not possible to mount the blocks on the gage side for some reason.
In yet another alternate embodiment, the nozzles are located above the railhead on the field side, but at a lateral position that allows the nozzles to stay clear of passing wheel flanges. The jets of lubricant fluid from the nozzles are aimed such that the lubricant projects downwardly and laterally towards the rail, where it is deposited on the rail.
Each nozzle holder block houses the nozzles and check valves for the different jets. Each nozzle directs the fluid jet in different directions on each rail in this way. The drawings show only two jets, one in the forward direction towards the approaching train and the other in the backward direction in which the train is moving. However, there can be many more jets if desired. The shot duration is determined by the amount of fluid to be applied to the rail. If the train is approaching at a very fast speed, the wheels may sometime intercept the jets fired towards it. However, the jets fired in the opposite direction (direction of train) will still fall on the rail. A computer controls the frequency and duration of each shot. The software is based on timing the approaching wheels such that at the instant the shot is fired, the nozzle holders are located intermediate the trucks of the car. However, this does not have to be so. A certain minimum number of shots (several) may need to be fired based on experience with the degree of lubrication needed. The logic for timing the shots is such that lubricant shots are not fired on the rail before passage of locomotive wheels. When three axles pass over the sensor, equal time apart or when time duration is longer between axles than those of cars, it is identified as a locomotive wheel and the lube shot on the rail is not fired. By this approach the locomotives and possibly the first car will pass before the system starts lubricating the rail. An environmentally clean top-of-rail curve lubricant, which flows smoothly under different temperature conditions, is used for this purpose. An enclosure or box located on the track wayside contains the computer, fluid and hydraulic and electrical control systems. Hoses from the box transmit fluid to each of the nozzle holders. The fluid is pressurized by a finite displacement pump or another system which can deliver controlled quantities of the fluid shot. Electrical connections are provided from the box to the two sensors mounted on the rail on either side of the nozzle holder block. AC power can be used for the box where available. If not, DC power from a battery, which is charged by solar cells, is used.
For optimum reduction of lateral forces, wear of wheel and rail, and damage to the track structure, it is essential to lubricate both regions 13 and 14 for both high and low rail for cars on a curve. It is best to lubricate accurately in controlled small quantities and skip the lubrication of the rail before passage of locomotive wheels altogether to avoid any wheel slip or loss of adhesion. This has not been possible to date other than by the wayside wheel lubricator system of Kumar, U.S. Pat. No. 6,585,085 which lubricates the treads and flanges of passing wheels. It works well in railroad yards at low car speeds. The present invention offers a method of lubricating both regions 13 and 14 of rails on curves for revenue service train cars for the benefit of a railroad's engineering department, which has the responsibility to protect the track on curves.
The distance from the nozzles 16, 17 to the sensors 19 and 20 should be selected based on the average speed of trains at the lubricator's location. By way of example and not by limitation, the sensors can be located seven or eight feet from the nozzles when the average train speed is 10 miles per hour. If the average train speed is 30 to 40 miles per hour, the sensors should be spaced about fifteen feet from the nozzles. High speed traffic of 60 to 70 miles per hour would best be handled by a sensor-to-nozzle distance of about twenty feet. While these precise figures could vary somewhat, the basic idea is to increase the distance as speed increases to allow sufficient time for the software to react to the sensors, fire a lubricant shot and have the shot land on the rail without interruption by a passing truck.
The supply lines are connected to a wayside box or housing 26. The housing 26 contains a finite displacement pump with motor 28, a lubrication tank 29 and a controller 27. The controller determines the quantity of lubricant to be fired in each shot with its control of the finite displacement pump. Other methods of control are possible. The pump and controller may be powered by AC current 33 or DC current 32. For DC current the power may be provided by a solar panel 34 mounted on the pole 35 and the power is processed by a power pack 31 to charge a battery 30. The battery 30 provides the electrical current and voltage to the motors connected to the pump motor 28. The frequency of firing the jet shots 21, 22 and 8, 9 is controlled by software in the controller. Thus, the amount of fluid applied to the top of the rail and gage side is fully controlled in order to reduce the friction between wheels of cars and rails in an accurate and controllable way.
The fluid jets 46 coming out of the nozzle discharge orifices 48, 49 are aimed at a small angle up and into the rail. The number of jets and the angle with the horizontal direction of the rail can be varied for different applications. A small angle with a vertical plane through the axis of the rail, towards the centerline of the rail, is essential in order to insure that the fluid rises in a nearly vertical plane above the railhead and then falls on to it. The angle of the jet can be between 1° and 90° above the horizontal with 5° being a preferred angle. The angle of the jet compared to the longitudinal axis of the rail can be 0.1° to 80° with 2° being preferred. The horizontal distance of the nozzle discharge orifice from the railhead can be between 1/16″ to 2″. Also, in order to be below the height of the wheel flanges rolling on the rail, gage side nozzle bodies must be between ¾ to 3 inches below the top of the rail, depending on the size of the wheel flanges and the railhead height. 2¼ inches below the top of the rail is preferred. Field side nozzle bodies can be closer to the top of the rail head, somewhere between ⅛ to 2 inches being suitable.
The nozzles are also aimed such that the jet slightly grazes a corner of the railhead. This causes the jet to disperse into a generally vertical sheet or curtain of fluid. Creating a curtain of fluid increases the length of the wetted area of the rail. That is, grazing the rail breaks up the jet into a curtain so that portions of it fall closer to the nozzle than would otherwise be the case. With the curtain some portions of the fluid jet will land at relatively close distance from the nozzle, other portions will land at intermediate distances from the nozzle, and still other portions will land at maximum distances from the nozzle. The curtain creates a continuously wetted area along the rail. In a typical installation the rail is wetted from about 3 feet to about 15 feet from the nozzle. If the jet were not dispersed in this manner it would still disperse naturally but in a smaller area and toward the far end of the jet's reach, somewhere in the vicinity of 10 feet from the nozzle. There are alternative ways to create the curtain, other than by aiming the jets to graze the rail. The nozzle discharge orifice could have a needle or the like that pricks the outgoing jet, causing it to disperse into a curtain of fluid.
Placement of the nozzle body 41 on the gage side 12 is the preferred mode because it enables lubrication both on top of the rail 13 and on the gage corner 14. In this arrangement, on a curve the lateral creep of the wheel helps to move the lubricant layer on the rail surface to get more into the wheel-rail contact area (
When the train approaches one of the sensors, the sensor detects passage of a wheel and turns the pumping system on. The sensor identifies passage of a locomotive truck by several methods. If there are three wheels spaced by equal time intervals, it is a locomotive truck. In other words the system does not fire on the passage of a three-axle truck. If it is a four-axle locomotive, the system will wait to determine the timing of additional axles and start firing only after passage of the first two-axle truck of the first car. Logic is based on the time lapse between consecutive wheel sensing and distances between axles of most available trucks of cars and locomotives. If there is a truck of unusual dimensions it will fool the software temporarily, causing the software to pause momentarily, reset itself, and start with the logic again. By this method the system will succeed in assessment of the passage of wheels the majority of the time.
The quantity of lubricant applied to the rail is intended to be very small, consisting of only a few milliliters per shot. The purpose of this is to develop a very thin film on the rail/wheel contacting surfaces of non-tractive car wheels and skip the lubrication of tractive locomotives wheels. This permits the reduction of lateral forces on the rail and wheel flange. Reduction of flange friction for all car wheels is also achieved. Since very small controlled quantities of the fluid are applied to the rail, a considerably cleaner track is achieved in comparison to the present grease bar lubrication method. Improved life of track, reduced cost of lubricant and track maintenance, increased wheel life and reduced possibility of car derailment are all achieved without compromising locomotive traction ability.
The nozzle bodies 16, 17 are connected hydraulically to the control box 26 which is powered by AC power 32 or DC battery voltage 33 charged with solar cells 34. As the train cars pass by the nozzle body 16, 17 the lead axle 43 of truck 54 triggers the shot but truck 55 and 56 wheels do not. In this way, there will be a shot corresponding to each car. If the amount of fluid applied to the rail is to be reduced there are two approaches by which this can be accomplished:
1) Decrease the amount delivered in one shot by the finite displacement pump.
2) If further reduction is desired, the frequency of taking a shot can be reduced from every car to every other car or every third car, etc.
There can be different variations of the control logic. Another scenario is firing the shot based on the speed of the train. The intervals of time between two different shots will be reduced as the speed of the train is higher. Under this approach, the lubricant shots will be fired at a frequency based on the speed of the train. The lubricant shots will deliver lubricant to the rail head surface, although occasionally one of the shots might get intercepted by a wheel.
An alternate embodiment of the lubricator is shown in
It is important to note that the described lubricator lubricates both the top of the rail and the gage corner at the same time. So far as the inventor is aware, this has not been done before.
It will be understood that the embodiments of the present invention which have been described are illustrative of some of the applications of the principles of the present invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention, including those combinations of features that are individually disclosed or claimed herein. For example, while the lubricator has been described as being used in curved sections of track, it could also be applied to tangent track for the purpose of reducing lateral forces on the rails. Also, while it is most convenient, and therefore preferred, to clamp the nozzle support brackets 35, 36 to the rail base, the bracket supporting the nozzle body could alternately be redesigned so as to be attachable to a tie or even supported by the ballast. Further, alternate forms of the pressurizing means are contemplated. A motor-driven pump could be used with solenoid valves controlled by a pulse width modulation method. An air compressor could be used with a diaphragm tank to apply pressure above the surface of the lubricant in the reservoir. Replaceable compressed air tanks could be used to pressurize the lubricant in the reservoir. Either of these arrangements would require some sort of valve in the supply line to the nozzle body. The sensor is described as a wheel sensor but alternately it could sense other parts of the car.
