Patent Application
20140088801
The present disclosure relates generally to a test system and method and, more particularly, a system and method for testing train brakes.
Monitoring systems for the railroad industry provide methods and apparatus for automatic determination of the conditions of wheels and bearings on passing trains. One apparatus for automatically detecting potential defects is described in U.S. Pat. No. 8,160,832. Different types of data are gathered from detectors or sensors that each provide new information about system defects, and the data are combined in an effort to reduce the rate of false indications.
Existing monitoring systems look for abnormally hot wheels or bearings—using “hot wheel” detectors or “hot box” detectors. In the case of U.S. Pat. No. 8,160,832, the system monitors data from various orthogonally related sensors, and combines the resulting independent data to reduce the rate of false indications. None of the existing systems provide a means for testing whether brakes are properly activating and deactivating from an operational perspective, rather than as a cause of a potentially serious problem once an actual “hot wheel” or “hot box” has been detected.
The system and method of the present disclosure solves one or more problems set forth above and/or other problems in the art.
In one aspect, the present disclosure is directed to a method of testing the performance of a wheel brake for a wheel on a train car. The method may include detecting a first temperature of the wheel in a testing area with the wheel brake deactivated. The method may also include activating the wheel brake, and detecting a second temperature of the wheel with the wheel brake activated. The method may further include determining a wheel brake condition based on the first and second temperatures of the wheel.
In another aspect of the disclosure, a system is provided for testing a wheel brake on a train car moving along a train track. The system may include a plurality of temperature sensors, each configured to detect a temperature of a wheel on the train car. The system may also include a processor configured to receive a first signal from a first one of the plurality of temperature sensors indicative of a first temperature of the wheel with the wheel brake deactivated. The processor may also be configured to receive a second signal from a second one of the plurality of temperature sensors indicative of a second temperature of the wheel after activating the wheel brake. The processor may be configured to determine a wheel brake condition based on the first and second signals.
In addition, train 100 may include a pneumatic braking system, which may include a main air line from the locomotive (not shown), from which pressurized air is supplied to various brake valves, such as brake valve 160 shown in
In various implementations, each truck 122, 124 with two or more axles 150, 152, 154, 156 per truck 122, 124 and two wheels 130, 132, 134, 136 per axle 150, 152, 154, 156 may be associated with a single brake valve 160. Wheels 130, 132, 134, 136 are shown at one end of respective axles 150, 152, 154, 156, and may be paired with matching wheels (not shown) at the opposite ends of their respective axles. In alternative implementations, each brake valve 160 may be associated with more than one truck 122, 124. Braking systems associated with each brake valve may operate, (and may fail) independently of one another. Therefore, various implementations may monitor wheel temperatures, as discussed in detail below, for wheels that are connected to the same brake valve together. Furthermore, the following discussions of individual wheels, associated individual wheel brakes, etc., will be understood by one of ordinary skill in the art to also apply to groupings of wheels, such as all of the wheels on a single truck, or all of the wheels on a pair of trucks connected with the same brake valve, etc.
Wayside “hot wheel” detectors (HWD) 211, 212, and 213 may be positioned along train track 170 to automatically sense the temperature of wheels of a passing train, and alarm when the wheel temperatures become too great for continued safe operation. HWD 211, 212, and 213 may include temperature sensors 222, 223, 224, 225, 226, and 227, which are configured to convert sensed infrared heat energy produced by a component such as a passing train wheel to an electrical signal that is proportional to the amount of heat output by the wheel relative to ambient temperature. One of ordinary skill in the art will recognize that there are a variety of other temperature sensing technologies also suitable for use with various implementations of the disclosure.
As shown in
The spaced pairs of wheel temperature sensors are included in a predesignated testing area 210 along the train track 170. Multiple testing areas similar to testing area 210 may be spaced along train track 170, with each testing area including two or more spaced pairs of wheel temperature sensors. The testing areas may be located along stretches of train track over varying terrains. Downhill stretches of train track may provide testing areas where braking of the train cars is performed under natural circumstances, and therefore does not require performing a special braking operation for testing the brakes when braking would not normally be performed.
The pairs of wheel temperature sensors 222 and 223, 224 and 225, and 226 and 227 placed along opposite sides of train track 170 may produce signals indicative of the temperatures for each wheel on a per axle basis, and may provide those signals to associated HWD 211, 212, and 213, respectively. Each HWD 211, 212, and 213 may also include associated wheel position sensors 232 and 233, 234 and 235, and 236 and 237, respectively.
As a train car wheel passes each HWD 211, 212, and 213, the associated pairs of wheel position sensors may provide signals to the associated HWD, which the HWD may use in defining a window when signals from the associated wheel temperature sensors are received by the HWD and converted into temperatures of the passing wheel. Each of the HWD 211, 212, and 213 may be positioned at wayside stations along train track 170, and may be communicatively coupled with a processor 215 of testing system 200. Processor 215 may be located remotely from train track 170, in a dispatch office, on board the train, or in one or more wayside stations. HWD 211 may communicate signal 252 to processor 215, HWD 212 may communicate signal 254 to processor 215, and HWD 213 may communicate signal 256 to processor 215. One of ordinary skill in the art will recognize that signals 252, 254, and 256 may be communicated to processor 215 through a wireless connection, over cellular in the form of a voice communication, over an ethernet connection, over a network, or through other means.
The processor 215 may also be configured to only activate temperature sensors 222, 223, 224, 225, 226, and 227 of HWD 211, 212, and 213 when associated wheel position sensors 232, 233, 234, 235, 236, and 237 indicate the presence of a wheel within the window between each pair of wheel position sensors. One of ordinary skill in the art will recognize that various implementations may include wheel position sensors 232, 233, 234, 235, 236, and 237 comprising physical proximity transducers positioned adjacent train track 170, as shown in
One of ordinary skill in the art will recognize that although processor 215 is illustrated as a single unit, the functionality provided by processor 215 could be provided instead by one or more processors. The one or more processors may be part of a server, client, network infrastructure, mobile computing platform, or a stationary computing platform, one or more of which may be contained in a dispatch office, on the train, in a single wayside housing, multiple wayside housings, or at remote locations communicatively coupled over wired or wireless networks.
The disclosed method and system may allow for testing the performance of a wheel brake on a train car by detecting a first reference temperature of a wheel with the wheel brake deactivated, and then activating the brake for a period of time or distance along the train track. A second, elevated temperature of the wheel may then be detected with the brake activated. A processor may be configured to determine a wheel brake condition by comparing the difference between the first and second wheel temperatures with a threshold. The processor may also be configured to perform other functions such as gathering data regarding the conditions of the wheel brakes on all wheels for each train car, and identifying patterns for each train car. Data gathered and processed by the processor may be used to identify when certain control actions should be taken, such as stopping the train to perform maintenance, scheduling future maintenance, performing autonomous control, etc.
Aspects of the present disclosure provide the functionality of detecting an improperly operating train brake through the recognition that a change in wheel temperature can be observed in conjunction with partial activation and deactivation of the wheel brake. A properly braking wheel may dissipate heat generated by the friction material in the brake shoe coming into contact with the wheel. In alternative braking systems such as hydraulic fluid braking systems, heat may also be dissipated as the rolling kinetic energy of the train wheels is transferred to the braking system through friction, effectively converting the kinetic energy into thermal energy. Hot wheel detectors include temperature sensors that are capable of detecting the temperatures of train wheels passing the temperature sensors. Rather than waiting for the temperature of the wheel to get above a predetermined threshold, at which continued operation of the train could be unsafe, aspects of the present disclosure contemplate using the temperature sensors to detect changes in temperature of a wheel from when the wheel brake is deactivated, to when the wheel brake has been activated.
In various implementations, the temperatures of one or more of the wheels on a truck may be averaged together or otherwise processed in arriving at a value that may be used in performing the comparisons of wheel temperatures with brakes activated and wheel temperatures with the brakes deactivated, as discussed in more detail below. Each temperature sensor may also be configured to sample a plurality of overlapping areas on any particular wheel that is passing. These “snapshots” of the temperature of the passing wheel may also be averaged together or otherwise processed to arrive at the value used in a comparison of temperature of a wheel with an activated brake to the temperature of that wheel with the brake deactivated.
In various implementations of the present disclosure, processor 215 may be configured to receive the temperatures, and compare the temperatures detected by different ones of the temperature sensors. In one example implementation, processor 215 is configured to compare temperatures of passing wheels with deactivated brakes as detected by temperature sensors 222 and 223 of HWD 211, with temperatures of the same wheels with activated brakes as detected later by temperature sensors 224 and 225 of HWD 212.
The coordinated functionality of processor 215, temperature sensors 222, 223, 224, 225, 226, and 227, and wheel position sensors 232, 233, 234, 235, 236, and 237, enables measurement of a first, reference wheel temperature when braking is deactivated and a second, elevated wheel temperature when braking is activated. The processor may be configured to compare the difference between the two temperatures with a threshold difference value for a determination of whether the difference between the temperatures is indicative of a properly operating brake. A malfunctioning brake could be caused by improperly functioning brake valves, worn brake shoes, or other circumstances. The processor 215 may also be configured to implement a control action if the comparison of the two temperatures results in a determination that the difference between the temperatures is less than the threshold difference, which may be indicative of a malfunctioning brake. The control actions implemented by the processor 215 may include, but are not limited to, sending an alert, sounding an alarm, sending instructions to be followed manually by a train operator, performing autonomous control of the train, scheduling maintenance functions to be performed at a later time, etc. Various implementations of this disclosure provide a testing system that may allow for the automated testing of every brake on every train car on a train as a train is moving along a train track.
Referring to
At step 320, processor 215 may be further configured to receive a signal 252 from HWD 211 and wheel temperature sensors 222 and 223 indicative of a first reference temperature for wheel 130 (and the matching wheel on the other side of the train) with the wheel brake and brake shoe 140 deactivated. At step 330, a wheel brake with brake shoe 140 may be activated to contact wheel 130 at less than full activation, and maintained in the partial braking condition for a predetermined distance until reaching the location of HWD 212. In various exemplary implementations, the distance between HWD 211 and HWD 212 may be any distance from several hundred yards, to approximately one half mile, to one mile or more.
At step 340, processor 215 may be configured to receive a second signal 254 from HWD 212 and associated temperature sensors 224 and 225 indicative of a second, elevated temperature of the wheel 130 (and the matching wheel on the other side of the train) with the wheel brake and brake shoe 140 activated. The distance between HWD 211 and HWD 212, and between associated wheel position sensors 232, 233, 234, and 235 may be selected to provide sufficient time, based on parameters such as the speed of the train, ambient conditions, etc., for a particular wheel with partially activated brakes to heat up by an amount that enables an accurate, measurable, and repeatable comparison of the difference between the first reference temperature and the second elevated temperature of the wheel 130.
At step 350, processor 215 may be configured to compare the first reference temperature and the second, elevated temperature of the wheel 130, and at step 360, determine whether the difference between the first and second wheel temperatures is greater than or equal to a threshold amount. If the difference between the first and second temperatures is greater than or equal to the threshold amount, processor 215 may return to step 310. If the difference between the temperatures is not greater than or equal to the threshold, which may be indicative of a malfunctioning brake, at step 370 processor 215 may be further configured to compare a total number of possibly malfunctioning brakes on one train car to an allowable percentage of potentially malfunctioning brakes on that car.
At step 380, processor 215 may be configured to implement one of the control actions described above if the number of potentially malfunctioning brakes is greater than or equal to the allowable percentage. In variations to these procedures, processor 215 may be configured to deactivate the brake 140 (or any other brake and brake shoe on any other wheel or combination of wheels) and receive a signal 256 from another set of temperature sensors 226 and 227 at HWD 213 indicative of the temperature of the wheels again with brakes deactivated when the train our 110 is still within the testing area 210. One of ordinary skill in the art will recognize that variations to the above-described procedures may include variations in the number of times a brake is activated and deactivated within a testing area, the number of times the temperatures are measured, the spacing of the HWD's, the spacing of the wheel position sensors, variations in the times when the processor 215 receives signals from the temperature sensors indicative of the temperature of a passing wheel, and variations in the relationships between these parameters.
The amount by which a brake may be activated in order to generate a detectable difference in temperature of the wheel from when the wheel brake is deactivated, may be less than full activation of the brake, e.g., approximately 10%-20% of full activation of the brake, approximately 5%-10% of full activation, or other ranges of percentages of full activation. By only activating a brake to this set amount in the designated test areas, excessive wear on the brakes can be avoided. Testing of the brakes in this manner will also allow for early determination of a malfunctioning brake, before the situation has gotten to the point that the “hot wheel” detector is sounding an alarm. Additionally, testing of the brakes may be performed while the train is moving, and using automated readings of wheel temperatures, rather than manual, physical inspections of every brake with the train stopped.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed brake testing system without departing from the scope of the disclosure. Other embodiments of the brake testing system will be apparent to those skilled in the art from consideration of the specification and practice of the brake testing system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
