1111111111111111 IIIIII IIIII 11111 1111111111 1111111111 1111111111 11111 111111111111111 11111111
`US 20070152107Al
`
`c19) United States
`c12) Patent Application Publication
`LeFebvre et al.
`
`c10) Pub. No.: US 2007/0152107 Al
`Jul. 5, 2007
`(43) Pub. Date:
`
`(54) RAILROAD TRAIN MONITORING SYSTEM
`
`Publication Classification
`
`(75)
`
`Inventors: William LeFebvre, West Chester, PA
`(US); Michael J. McCann,
`Wilmington, DE (US)
`
`Correspondence Address:
`SYNNESTVEDT & LECHNER, LLP
`1101 MARKET STREET
`26TH FLOOR
`PHILADELPHIA, PA 19107-2950 (US)
`
`(51)
`
`Int. Cl.
`B61L 3/00
`(2006.01)
`(52) U.S. Cl. ........................................................ 246/169 R
`
`(57)
`
`ABSTRACT
`
`(73)
`
`Assignee: AFS-Keystone, Inc., Granite City, IL
`(US)
`
`(21)
`
`Appl. No.:
`
`11/615,309
`
`(22)
`
`Filed:
`
`Dec. 22, 2006
`
`Related U.S. Application Data
`
`(60)
`
`Provisional application No. 60/753,593, filed on Dec.
`23, 2005.
`
`Railcar monitoring utilizes instrumented, flexible pads sup(cid:173)
`ported within the truck pedestal jaws on the bearing adapt(cid:173)
`ers. The pads contain sensors for monitoring temperature
`pressure, shifting loads, truck hunting and the like and have
`circuitry for processing information received from the sen(cid:173)
`sors and for processing and reporting departures of perfor(cid:173)
`mance variables to a remote source. The system cyclically
`activates polling each pad on a car and communicates
`signals of critical departures and car identity to a remote
`source.
`
`24a
`
`24
`
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`3
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`3
`
`3
`
`
`Page 1 of 13
`
`EX1005
`Petitioner Hum (223)
`
`

`

`Patent Application Publication
`
`Jul. 5, 2007 Sheet 1 of 3
`
`US 2007/0152107 Al
`
`23a
`
`~~~r-----ir=!==,-----;.=Jb==-1\2
`22
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`5
`
`19
`FIG.3
`
`17
`
`18
`
`
`Page 2 of 13
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`

`

`Patent Application Publication
`
`Jul. 5, 2007 Sheet 2 of 3
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`US 2007/0152107 Al
`
`4 13
`16
`
`FIG.4
`
`2a
`
`
`Page 3 of 13
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`

`

`Patent Application Publication
`
`Jul. 5, 2007 Sheet 3 of 3
`
`US 2007/0152107 Al
`
`- - - FIG.5-----
`
`-6
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`
`
`Page 4 of 13
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`

`

`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`1
`
`RAILROAD TRAIN MONITORING SYSTEM
`
`FIELD OF THE INVENTION
`
`[0001] This invention relates to a monitoring system for
`railroad trains and the like, and more particularly a system
`that uses an instrumented roller bearing adapter pad to detect
`the occurrence and cause of poor performance at wheel set,
`truck, freight car or train level.
`
`BACKGROUND OF THE INVENTION
`
`[0002] More than ever, railcar owners and operators need
`a better understanding of how their assets are performing.
`With heavier cars in service, there is a greater need to
`identify "bad actors" (cars which can damage track infra(cid:173)
`structure and lead to derailments) as soon as their perfor(cid:173)
`mance becomes unacceptable. There is also a need to
`increase average train speed by improving high speed per(cid:173)
`formance and reducing unplanned service interruptions
`through mechanical failures. Car owners increasingly seek
`to implement preventative maintenance programs to avoid
`mechanical failures and schedule repairs at a facility and
`time of their choice. Finally, with more automation of rail
`operations and increasing regulation to improve safety, the
`railroad industry needs new ways to monitor the perfor(cid:173)
`mance of trains, cars and railcar trucks.
`
`[0003] Some of the performance criteria that need to be
`monitored include roller bearing condition and temperature,
`roller bearing adapter displacement, wheel condition, truck
`hunting/warp/binding, brake
`status and performance,
`whether a partial derailment has occurred and potentially
`problematic track condition. Since some of these perfor(cid:173)
`mance problems could lead very quickly to a catastrophic
`failure of the train, it is desirable to monitor and report
`exceptions to the locomotive or to a central data handling
`facility as quickly as possible. Further, given the demanding
`environment in which railroad trains operate, any system
`must be rugged, reliable and able to operate for long periods
`with little or no maintenance. In addition, to be cost effec(cid:173)
`tive, it should not add significant cost to install and maintain
`the system. Since there are more than 1.5 million freight cars
`in North America alone, and a system of monitoring all cars
`in use is highly desirable, any such system need to be able
`to deal with a very large address a very large number of
`potential devices.
`
`[0004] One approach widely adopted in North America is
`to use wayside defect detectors at fixed locations throughout
`the railroad network. Detectors measuring bearing tempera(cid:173)
`ture (hotbox detectors) are common, while other wayside
`detectors to measure wheel impacts, bearing condition (from
`acoustical signatures) and lateral forces are gradually being
`introduced. However, while one detector can monitor many
`freight cars as they pass, they can only provide a spot check
`on performance. It is quite possible that defects will only
`become apparent and escalate to a critical level between
`detectors. A system which is continuously monitoring railcar
`performance is needed.
`
`[0005] Another approach to railcar performance monitor(cid:173)
`ing has been to use on-board instrumentation. One such
`prominent system has been developed for the Federal Rail(cid:173)
`road Administration. In this and other similar systems, a
`number of instruments on different areas of a freight car are
`used to make discrete measurements before being commu-
`
`nicated to a central hub on the freight car. While providing
`a superior solution to that provided by wayside monitors,
`wiring, complexity and costs
`increase the investment
`required to monitor the cars.
`
`SUMMARY AND OBJECTS OF THE
`INVENTION
`
`[0006] This invention has the objective of providing
`means for continuously, while in service, monitoring the
`behavior and condition of the trucks, wheels and bearings of
`a railroad car and provide both regular assurance of proper
`performance and, as necessary, warning of impending or
`actual failure in a timely and useful manner to the operators
`and owners of the train whereof if forms a part.
`
`[0007]
`It is a further objective of this invention that the
`performance of the railcar and its components could be
`combined with operating data from the locomotive to pro(cid:173)
`vide a complete train monitoring system.
`
`[0008]
`It is a further objective of this invention to provide
`such functionality with minimal recourse to making wired
`electrical connections either between components mounted
`on the trucks of the railcar or between components mounted
`on the trucks and components mounted on other parts of the
`car and other parts of the train, including the locomotive.
`
`[0009]
`It is a further objective of this invention that the
`components can be inserted or removed for inspection and
`repair or replaced during normal maintenance work on the
`railcars.
`
`[0010]
`It is a further objective of this invention to provide
`means for the timely analysis of measurements made during
`operation of the train so that the information about perfor(cid:173)
`mance or failure can be sent in a concise manner so that there
`is no need for detailed measurements to be transmitted.
`
`[0011]
`It is a further objective of this invention that the
`messages sent about performance or failure contain suffi(cid:173)
`cient information that the exact location on the train of the
`item or items in question can be unequivocally determined,
`and that the location of the train, or indeed of the freight car
`can be reported, should that information be available.
`
`[0012]
`It is a further objective of the invention that when
`operating wirelessly, it can be expanded to exploit the
`available choices of operating frequencies (channels) to give
`relief from interference between the successive (adjacent)
`cars in a train or from other equipment operating in the same
`band of frequencies.
`
`[0013] While the discussion which follows describes the
`vehicle as a freight car, it will be understood that the same
`methods are applicable to any railroad or, in some instances,
`other multi-axle vehicles. Furthermore, while the descrip(cid:173)
`tion which follows features a freight car with two trucks ( or
`bogies ), it is applicable to almost any configuration with
`more or less trucks or axles.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[0014] FIGS. 1-3 are schematic views showing the
`arrangement of components suited for use in carrying out the
`objectives of the present invention;
`
`[0015] FIG. 4 is an exploded perspective view of portions
`of a railcar truck illustrating the position of an instrumented
`pad of the invention with respect to the railcar truck; and
`
`
`Page 5 of 13
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`

`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`2
`
`[0016] FIGS. 5-7 are schematic views illustrating alterna(cid:173)
`tive configurations of elements of the invention.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENTS
`
`[0017] Turning now to FIGS. 1, 2 and 4, trucks 1, shown
`diagrammatically, each carry two axles 2 each with two
`wheels 3. The axle bearings 2a and bearing adapters 4, best
`shown in FIG. 4, are configured so that each bearing
`transmits the load which it carries and heat that it may
`generate through pads 16 and to the truck.
`
`[0018] FIG. 4 illustrates a portion of a railcar truck 1
`showing the relationship of an instrumented pad 16 relative
`to other truck parts. In FIG. 4, one end of a truck side frame
`12 is shown. Each side frame has a pair of downwardly
`extending pedestal jaws 13. Parallel side walls 14 of each
`pedestal jaw along with a roof section 15 combine to form
`a pedestal jaw opening.
`
`[0019] The truck also includes bearing adapters 4, one of
`which is shown in FIG. 4. The adapters have a generally
`rectangular upper surface with depending legs extending
`from the corners of the top structure. The legs have facing
`curved side surfaces which are configured so as to rest on the
`outer surface of a bearing 2a mounted on the end of wheel
`bearing axle 2. The adapter is typically comprised of cast
`steel. Adapter pad 16 is generally rectangular in plan view
`and has depending legs. The adapter pad 16 is preferably
`comprised of a cast or injected molded elastomeric polymer.
`The adapter pad 16 is formed to seat upon the upper surface
`of adapter 4 which, as indicated above, seats in turn on the
`bearing. The adapter and details of the pad as they relate to
`its function as a load bearing and attenuation means are more
`particularly described in U.S. Published Application No.
`2005/0268813, dated Dec. 8, 2005.
`
`[0020] Referring further to FIG. 2, the pads 4 are seated on
`the upper rectangular surface of the bearing adapter. Each
`bearing transmits the loads which it carries and heat that it
`may generate through the adapter to the pad it carries and,
`thus, to the railcar truck.
`
`[0021] FIG. 3 shows, in schematic form, an adapter pad 16
`modified to carry out the objectives of the present invention.
`The pad contains a plurality of sensors 5 which are prefer(cid:173)
`ably embedded into its upper, side and lower surfaces or into
`other locations such as its end surfaces as may be necessary
`for the purposes of the invention as explained more fully
`below. In preferred form, the pad 16 has an extended
`attachment portion 17 located so as to be relatively isolated
`from the forces transmitted through the adapter 16. The
`extended portion 17 contains a power source 18, an analog/
`signal conditioning means and analog to digital conversion
`means and an associated microprocessor unit 19 and a
`communications unit 20 which is preferably a low power
`radio transmitter/receiver having an antenna 21. The sensors
`are electrically connected to the analog to digital conversion
`circuit unit and the microprocessor unit which, in turn, is
`connected to and controls the communications unit by
`means of which messages can be sent and received. Various
`means of supplying power to the pad may be employed. The
`source of power may be a battery delivering sufficient
`voltage and having sufficient energy storage capacity so that
`when turned on periodically and briefly, as described here-
`
`inafter, the pad can be functional for several years, consis(cid:173)
`tent with the normal service life of the bearing components
`used in the trucks.
`
`[0022] Alternatively, the power source may consist of an
`energy scavenging device which supplies energy to a
`rechargeable battery or capacitor. A strain generated electri(cid:173)
`cal power source may be employed. Although the energy
`source may be a source mounted on the car body, it is
`preferred that it be on the truck and most preferably on the
`extension to the pad so as to avoid the need for electric
`wiring between relatively movable car parts.
`
`[0023] FIGS. 1-3 further illustrate a railroad freight car 22
`having trucks 1 with pads 16 with their associated sensors
`and control and communication circuit units 19 and 20. In
`the example described, each truck carries four pads 16 (one
`for each bearing) each having a power source 18, control
`circuit unit 19 and a communications unit 20, preferably
`comprising a radio transmitter/receiver.
`
`[0024] Mounted on the railcar body, preferably at a point
`at about midway between the two railcar trucks is a data
`control unit 23 also having a radio/receiver which has the
`ability to communicate with the radios on the pads 4 on its
`own railcar together with a microprocessor whose functions
`will be described hereinafter. The data control unit 23 is
`linked by cable 23a to a communications device 24 shown
`herein as being on top of the railcar, although other positions
`may be appropriate, depending on factors such as the type of
`car to which the invention is applied. Under some circum(cid:173)
`stances and for some car types, the data control unit and the
`communications device may be contiguous.
`
`[0025] The communications device 24 is advantageously
`powered by a solar cell represented by reference character
`24a or other electrical means having the capability of
`maintaining continuous
`functionality. Communications
`device 24 serves to link the railcar either directly to the
`locomotive drawing the train so that the engineer or other
`crew personnel have immediate notice of problem cars.
`Optionally, communication may be via track side automatic
`equipment identification means or to a cellular or satellite
`radio system or other communication equipment to moni(cid:173)
`toring stations as desired by the user. In the event that wired
`communication from the locomotive is available throughout
`the train as, for example, if electronic braking becomes
`standard, then the communications device may be connected
`to this communication line. The power supply for the
`communications device 24 may also provide power for the
`data control unit 23a, in which case the electrical connection
`23 may be a multi-connector link.
`
`[0026] Also shown in FIG. 1 is a hand-held unit 23b
`containing a microprocessor and the radio for communica(cid:173)
`tion with the instrumented pad 16 by its radio and also with
`the data control unit 23. Unit 23b, hereinafter called a
`"registrar", is designed with very limited signal transmission
`capability so that it must be placed physically close to the
`pads 16 or the data communications unit 23 for communi(cid:173)
`cation to take place. This insures that the operator will
`communicate with only one such device without similar
`devices on other cars on the same or a nearby train receiving
`the radio transmissions.
`
`[0027] Although the use of a radio for making the com(cid:173)
`munication by the registrar is preferred, direct electrical
`
`
`Page 6 of 13
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`

`

`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`3
`
`contact could be employed. However, because of the harsh
`environmental conditions to which railcars are exposed,
`direct electrical contact would be liable to reduce reliability
`and would be more time consuming to carry out, especially
`when communication with a large number of cars is neces(cid:173)
`sary. The use of the registrar in carrying out the functions of
`the invention will be described further below.
`[0028] At this point, it should be noted that a feature of the
`invention is to facilitate ascertaining the address for radio
`communication at the time of installation of a pad or during
`replacement of a pad or a data control unit. For this purpose,
`as an alternative to radio communication, a radio frequency
`identification (RFID) tag or a corresponding bar code or
`other readable version of the extended address which can be
`read out and recorded by the registrar could be employed.
`[0029] While the antennae shown in FIGS. 1 and 3 are
`schematically illustrated as of wire or rod form. In practice,
`they may be micro-strips or conformal arrays and may be,
`for example, metallic conductors on a ceramic substrate.
`[0030] Likewise, in place of battery power for the instru(cid:173)
`mented pads an onboard electrical supply may be available
`in the railcar and could be employed if available. Alternative
`energy scavenging devices which derive energy from the
`rotation of the wheels could be used to generate electrical
`power. As a practical matter in choosing a source of power,
`high priority should be given to a power supply most likely
`to function for several years without the need for battery
`replacement or the need to perform other maintenance work.
`[0031] As noted above, it is a feature of the invention that
`the radios within the pads 16 and the data control units 23
`need only communicate over a very short range. For this
`purpose, radios conforming to the IEEE802.15.4 standard
`for wireless sensor networks are preferable. This is the short
`range standard of which the ZigBee sensor network systems
`is exemplary. The power levels are low and range is limited
`but all that is required is generally the ability to communi(cid:173)
`cate between the pads on the trucks of a particular car and
`the data control units of that car or with a registrar held by
`a workman standing close by the car. The existence of
`standards for the data formats and open source software for
`using these systems with capable micro-controllers makes
`this a preferable option. An especially compelling advantage
`to radio transmission is that wiring on the trucks and wiring
`from trucks to railcar is undesirable as being susceptible to
`breakage, and wiring along the length of a freight train very
`unlikely to be acceptable unless industry wide adoption of
`electronic brakes or the like is universally adopted.
`[0032] Means for wireless communication based on the
`IEEE standard are available and adaptable to allow the
`instrumented pads and data control units to establish a
`network of connections without external intervention. They
`can be set up to recognize the relationship of truck and axle
`location on a railcar or set up so that the digital communi(cid:173)
`cation unit is informed of the configuration providing
`thereby a multi-hop means of linking the network together.
`Radios used in carrying out the above aspects of the inven(cid:173)
`tion are intended to be operated intermittently at low power.
`Several frequency bands are acceptable in various parts of
`the world. A suitable available frequency at which the radios
`will be operating in North America is about 2.4 GHz.
`Although it is preferably expected that the format and
`coding of messages will conform to the aforementioned
`IEEE standard, other arrangements are feasible.
`
`In an exemplary system, the instrumented pads 4
`[0033]
`contain several sensors for measurement of dynamic and
`static vertical loads and shear or lateral forces imposed by
`the railcar truck and hence by the freight car by the bearing
`adapters. Conversely, these are the forces which the axles,
`themselves attached rigidly to the wheels, and subject to
`track irregularities, are applying to the truck. The exemplary
`instrumented pads 16 also carry temperature sensors to give
`an indication of the temperature of the associated bearing,
`since it is important for safety that a bearing does not
`become overheated.
`
`[0034] With reference again to FIGS. 1-3, in operation, the
`microprocessor on an instrumented pad 16 is normally in a
`passive, low power state, but is programmed to switch on
`briefly, periodically. It gathers readings from each of the
`sensors and performs preliminary analysis of the readings.
`The rational for the choice of sampling frequencies and the
`selection of sensors to be read is based on the type of
`behavior being monitored and the particular application.
`Sampling should be at a frequency several times the highest
`frequency to be detected from the data. More frequent
`sampling will gain no further intelligence but increase power
`consumption.
`
`[0035] The periodicities of sampling and of reporting are
`controlled by the data control unit 23. Nevertheless, should
`the pads detect indications of fault or impending failure, the
`microprocessor on the pad may be programmed to switch on
`the radio which it controls and send an appropriate message
`via the radio to the data control unit 23. An example of such
`an event could be a sudden increase in temperature. A large
`voltage spike generated by the power scavenging device
`may also be used to activate the pads microprocessor if it
`were then in a low power state. In the absence of such a
`problem, the pad microprocessor follows its given schedule
`which would normally result in its being in a low powered
`state most of the time.
`
`[0036] The data control unit 23 is intended to serve several
`purposes. It coordinates the timing of the cyclic testing
`performed by the instrumented pad microprocessor and the
`timing of the messages issuing therefrom. As an aggregator
`of information, it is programmed to compare information
`from all of the trucks on the railcar and draws inferences
`from them as to the status of the car, for example, the data
`control unit uses inference engine techniques to identify
`unsatisfactory behavior such as swaying, bouncing or even
`partial derailment. It passes on information from the com(cid:173)
`munications device 24. For example, the communications
`device 24 may include a means of measurement such as a
`global positioning system to provide information about
`vehicle speed which is useful in checking truck behavior
`such as hunting. This information may also be used to inhibit
`sensor checks when no purpose is thereby to be served in
`order to preserve energy usage.
`
`[0037] Likewise, if desired, detectors of factors such as
`ambient temperature and humidity (rain, snow and icing)
`can be built into the communication device 24 or the data
`control unit 23 in the distributed inference engine functions
`for use described below. Additionally, the data control units
`23 or the communications device 24 may contain a triaxial
`accelerometer or rate gyro for triggering certain analysis
`modes or verifying readings made by the pad and providing
`information on a variety of car body motions.
`
`
`Page 7 of 13
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`

`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`4
`
`[0038] As a conduit, the data control unit 23 passes
`messages on to the communications device 24 for onward
`transmission to the locomotive or to other remote receivers
`and receives, in tum, for the purpose of its own analysis and
`distribution to the pads, when appropriate, information or
`instruction as, for example, from the locomotive or from
`other remote sources.
`
`[0039] Alternative configurations for the monitoring sys(cid:173)
`tem described in FIGS. 1-3 are illustrated in FIGS. 5-7. In
`the embodiment shown in FIG. 5, each instrumented pad 16
`has its own microprocessor and radio. This arrangement is
`intended to use a protocol for networking which allows the
`messages to be passed between pads on their way to and
`from the digital communications unit 23.
`
`[0040]
`In the embodiment of FIG. 6, all of the pads 16
`from one truck communicate with a single microprocessor
`and radio unit 24 passing along multi-core cables 27. This
`minimizes the number of electronic components at the cost
`of making a large number of wire connections on the truck.
`The computational services performed in the microproces(cid:173)
`sor unit on the truck may be somewhat different from those
`in the microprocessor unit of FIG. 5. In this embodiment, all
`the analog to digital conversion functions are performed in
`the microprocessor and any inference functions performed
`there make assessments for all sensors for all pads on the
`truck.
`
`[0041] A further alternative embodiment is shown in FIG.
`7. In FIG. 7, each instrumented pad 16 has its own analog
`to digital conversion unit which may be incorporated into a
`microprocessor 28 on the particular pad. Those micropro(cid:173)
`cessors can then communicate with the single data handling
`unit 25 on the truck and hence to the data control unit 23. As
`in the configuration of FIG. 6, any inferences or data
`analysis performed at unit 25 takes account of information
`from all the sensors on all the pads on the truck.
`
`[0042] Other options include standard CANBus commu(cid:173)
`nication schemes where wired links are used. In addition,
`CANBus or other standards may be implemented in the
`event of wide scale implementation of electronically con(cid:173)
`trolled pneumatic brakes potentially providing other options
`for communication schemes.
`
`[0043] Communications along the train may be provided
`in a variety of ways. The WiFi (IEEE802.15.11 standard)
`may be appropriate for very long freight trains. For com(cid:173)
`munication along passenger trains, Rail Transit Vehicle
`Interface Standard, IEEE1473-199 would be applicable.
`
`[0044] Furthermore, it should be noted that, in principle, it
`would be feasible to let the instrumented pads communicate
`along the train, passing messages from one freight car to the
`next. However, for long trains, this causes a message to
`make many hops which is essentially less reliable than a
`single, more powerful link from each car to the locomotive
`or other remote location. Other problems include the like(cid:173)
`lihood that trains will be reconfigured with freight cars
`possibly being removed or shuffled or the train being pulled
`by a locomotive at its opposite end. Any such network
`depending upon pad-to-pad links from car-to-car would
`require reconfiguration of the train in marshalling yards.
`
`[0045] As indicated above, it is a feature of the invention
`to have appropriate means of addressing and identifying
`each and every instrumented pad in railcars used in the
`
`system. Further, it is necessary that the instrumented pads on
`trucks on adjacent freight cars, be they on the same train or
`not, continue to function while within each other's radio
`range without mutual interference. It must be possible to
`form trains from any freight cars and to replace a single pad
`on a truck without having to replace all the other pads on the
`truck or the freight car. Even if there are no problems to
`report, it is important that the system provide assurance that
`it is still functioning properly. The preferred system
`described herein uses messages initiated by the instrumented
`pads for this purpose. The alternative of using polling by the
`data control units to check the status of the instrumented
`pads requires the pads to switch on and act as receivers at
`accurately controlled times and for periods which require
`longer operation at full power than if they are allowed to
`send messages based on their own timing with the require(cid:173)
`ment that the data control units is always in a receiving
`mode.
`[0046] The instrumented pads which are to be mutually
`interoperable with the corresponding data control units must
`all use matching
`frequencies. The aforementioned
`IEEE802.15.4 standard designates frequencies or channels
`in each frequency band. For example, in the ISM band, at 2.4
`GHz there are 26 channels. There is also a standard for the
`pattern of messages such that each form a packet of a
`multiplicity of 8-bit bytes of data wherein each byte has a
`preassigned meaning. Within this pattern, one byte is
`assigned for a group number and two bytes are assigned for
`an address within a group. Another byte is assigned for the
`type of message which might be interpreted as a command.
`The associated radio receivers and their controlling micro(cid:173)
`processors are designed to ignore messages received from a
`source in a different group. They do not detect messages on
`other frequencies then their chosen operating frequencies.
`However, they can change operating channels (frequency)
`under program control. They can act appropriately on mes(cid:173)
`sages that belong to their own group. For use on railroads,
`a larger number of devices than can be covered by the
`two-byte address will be needed and, furthermore, means
`has to be provided so that a data control unit can recognize
`messages from instrumented pads on its own freight car.
`Instrumented pads have to be able to recognize messages
`from their own data control unit and both have to be able to
`tolerate potential interference from instrumented pads and
`data control units on other nearby freight-cars either in the
`same train or a passing train. They also have to be able to
`tolerate potential interference from other devices operating
`in the same unlicensed band.
`[0047] The identification number or address may be pro(cid:173)
`grammed into the electronics module at manufacture.
`[0048] The given address for an instrumented pad may
`additionally or alternatively be stored in an RFID (radio
`frequency identification) tag on or embedded into each pad
`4. The physical placement of the pad on the truck results in
`it being near to the trackside. Specifically, it could be on the
`outer side of the side frame of the truck and, thus, near to any
`trackside monitoring equipment. That provides the oppor(cid:173)
`tunity for at least the recognition of passing devices by the
`fixed equipment and, if active RFID tag technology is used,
`to allow for an alternative communication route from car to
`central data repository or the owners.
`[0049] The given address may conveniently be visible as
`a readable number optionally with a barcode for the conve-
`
`
`Page 8 of 13
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`

`

`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`5
`
`nience of users, though the demanding operational environ(cid:173)
`ment may make this alternative of limited use.
`
`[0050]
`It will be apparent that any addressing scheme
`which provides sufficient individual addresses or identities
`may be used. The address of the pad may be made con(cid:173)
`forming to the extended Internet Protocol (IPv6) addressing
`scheme, using 6 bytes so that these devices can have their
`own IP addresses.
`
`[0051] The preferred embodiment described below can be
`augmented to use multiple channels (radio frequencies)
`thereby providing a means of virtually eliminating interfer(cid:173)
`ence between adjacent cars in a train.
`
`[0052] The underlying purpose of the invention is to be
`able to monitor the behavior of all the trucks and bearings
`and wheels on a train. An alarm message must get through
`from any railcar to the locomotive or to the remote data
`handling service as quickly as possible, preferably within a
`few seconds.
`
`[0053] However, the burden of transmitting all the data
`that might be sampled in performing such monitoring is
`extremely large and, for the most part, detailed data is not
`significant. Preferably, only the observations which imply
`some fault or misbehavior are recognized. To reduce the
`radio traffic to manageable proportions, the system is
`designed to process the raw sensor data, looking for signs of
`trouble and then send only essential indicative information.
`To this end, a distributed inference engine is used, sharing
`the essential functions between the microprocessors at the
`instrumented pads and at the data control unit 23. It is a
`purpose of this invention to reduce the radio traffic between
`pads and data control unit so part of the data analysis is done
`at the pads and only relevant information is transmitted to
`the data control unit from the pads for further analysis and
`recognition of faults.
`
`[0054]
`In the example system illustrated above, the micro(cid:173)
`processors 19 at the instrumented pads 16 take a series of
`measurements and treat them as a time series. The search
`algorithms