I 1111111111111111 11111 lllll lllll 111111111111111 11111 11111 111111111111111111
`US007688218B2
`
`c12) United States Patent
`LeFebvre et al.
`
`(IO) Patent No.:
`(45) Date of Patent:
`
`US 7,688,218 B2
`Mar.30,2010
`
`(54) RAILROAD TRAIN MONITORING SYSTEM
`
`(75)
`
`Inventors: William LeFebvre, West Chester, PA
`(US); Michael J. McCann, Wilmington,
`DE (US)
`
`(73) Assignee: Amsted Rail Company, Inc., Granite
`City, IL (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 388 days.
`
`(21) Appl. No.: 11/615,309
`
`(22) Filed:
`
`Dec. 22, 2006
`
`(65)
`
`Prior Publication Data
`
`US 2007/0152107 Al
`
`Jul. 5, 2007
`
`Related U.S. Application Data
`
`5,347,871 A
`5,372,435 A
`5,381,090 A
`5,381,692 A
`5,440,184 A
`5,446,451 A
`5,503,030 A *
`5,642,944 A
`5,682,139 A
`5,810,485 A *
`6,127,672 A
`6,161,962 A
`6,179,471 Bl
`6,263,265 Bl
`6,301,531 Bl
`6,324,899 Bl *
`6,441,324 Bl
`6,535,135 Bl
`6,668,216 B2
`6,695,483 B2
`
`9/1994 D' Andrea et al .............. 73/775
`12/1994 Genero et al. ............... 384/448
`1/1995 Adler et al. ................. 324/174
`1/1995 Winslow et al ................ 73/593
`8/1995 Samy et al. ................... 310/90
`. ............ 340/682
`8/1995 Grosskopf, Jr.
`4/1996 Bankestrom ........... 73/862.627
`7/1997 Dublin et al.
`............... 384/102
`10/1997 Pradeep et al ............... 340/539
`9/1998 Dublin et al.
`............... 384/626
`10/2000 Danisch ................. 250/227.14
`12/2000 French et al.
`............... 384/459
`1/2001 Moretti et al.
`.............. 384/448
`7/2001 Fera ............................ 701/19
`10/2001 Pierro et al.
`.................. 701/29
`12/2001 Discenzo ................... 73/53.05
`8/2002 Stimpson .................... 177/137
`3/2003 French et al.
`............... 340/682
`12/2003 Mays .......................... 70 l/ 19
`2/2004 Sakatani et al. ............. 384/448
`
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`(60) Provisional application No. 60/753,593, filed on Dec.
`23, 2005.
`
`GB
`
`2 295 207
`
`5/1996
`
`(Continued)
`
`Primary Examiner-Anh V La
`(74) Attorney, Agent, or Firm-Fox Rothschild, LLP
`
`(57)
`
`ABSTRACT
`
`Railcar monitoring utilizes instrumented, flexible pads sup(cid:173)
`ported within the truck pedestal jaws on the bearing adapters.
`The pads contain sensors for monitoring temperature pres(cid:173)
`sure, shifting loads, truck hunting and the like and have cir(cid:173)
`cuitry for processing information received from the sensors
`and for processing and reporting departures of performance
`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.
`
`33 Claims, 3 Drawing Sheets
`
`(51)
`
`Int. Cl.
`G08B 21/00
`(2006.01)
`(52) U.S. Cl. ....................... 340/682; 340/438; 384/459;
`246/169 R
`Field of Classification Search ................. 340/682,
`340/870.17, 870.26, 870.3, 631, 632, 438,
`340/902-905; 73/53.05; 384/459, 446, 448,
`384/456, 626; 246/169 R, 122 R, 292, 473 R
`See application file for complete search history.
`
`(58)
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,718,040 A
`4,812,826 A
`5,140,849 A
`
`2/1973 Freeman et al. ............... 73/146
`3/1989 Kaufman et al ............. 340/682
`8/1992 Fujita et al. ................... 73/593
`
`24a
`
`24
`
`23a
`
`==~;;.---.=t=r-----.:===~:;-J\23b
`22
`
`3
`
`3
`
`23
`
`3
`
`
`Page 1 of 14
`
`EX1015
`Petitioner Hum (223)
`
`

`

`US 7,688,218 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`6,882,851 B2
`6,945,098 B2
`6,948,856 B2
`7,014,368 B2
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`7,034,660 B2
`2003/0146821 Al
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`2006/0042734 Al
`2006/0080048 Al
`
`4/2005 Sugar et al. ................. 455/454
`9/2005 Olson ............................ 73/86
`9/2005 Takizawa et al ............. 384/448
`3/2006 Morita et al.
`............... 384/448
`3/2006 Okada ........................ 384/448
`4/2006 Watters et al ............ 340/10.41
`8/2003 Brandt ...................... 340/10.1
`12/2004 Carr et al. ................... l 77 /136
`2/2005 Gall ............................ 73/715
`9/2005 Matzan ................... 246/169 A
`12/2005 VanAuken .............. 105/218.1
`3/2006 Turner et al. ............. 152/154.2
`4/2006 Kessler et al
`................. 702/35
`
`2006/0154398 Al
`2006/0207336 Al
`2007/0018083 Al
`2007/0095160 Al
`2007/0186642 Al
`2007 /0208841 Al
`2007/0255509 Al
`2008/0064941 Al
`
`7/2006 Qing et al. .................... 438/48
`9/2006 Miyazaki ..................... 73/760
`1/2007 Kumar et al.
`.......... 250/227.14
`5/2007 Georgeson et al. ............ 73/866
`8/2007 Sano et al. .................... 73/172
`9/2007 Barone et al ................ 709/223
`11/2007 Lefebvre et al ............... 702/33
`3/2008 Funderburk et al. ......... 600/347
`
`FOREIGN PATENT DOCUMENTS
`
`JP
`WO
`
`63236937 A
`WO0l/15001
`
`10/1988
`3/2001
`
`* cited by examiner
`
`
`Page 2 of 14
`
`

`

`U.S. Patent
`
`Mar. 30, 2010
`
`Sheet 1 of 3
`
`US 7,688,218 B2
`
`r 240
`
`FIG.I
`
`23a
`
`IHI.-----, D
`ff ff IJ
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`1111111111111
`~~~=---~~--~~=~~23b
`22
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`3
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`2
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`4
`
`5
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`16
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`5
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`r-
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`-
`
`19
`
`FIG.3
`
`18
`
`17
`
`
`Page 3 of 14
`
`

`

`U.S. Patent
`U.S. Patent
`
`Mar. 30, 2010
`Mar.30, 2010
`
`Sheet 2 of 3
`Sheet 2 of 3
`
`US 7,688,218 B2
`US 7,688,218 B2
`
`
`
`4 13
`16
`
`FIG.4
`
`2a
`
`Page 4 of 14
`
`
`Page 4 of 14
`
`

`

`U.S. Patent
`
`Mar. 30, 2010
`
`Sheet 3 of 3
`
`US 7,688,218 B2
`
`ad 24~23a ITT ITJ
`
`, _____ FIG.5----
`\
`16
`
`16 27
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`25 ~23
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`17 16 /
`27
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`
`
`Page 5 of 14
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`

`

`US 7,688,218 B2
`
`1
`RAILROAD TRAIN MONITORING SYSTEM
`
`FIELD OF THE INVENTION
`
`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 occur(cid:173)
`rence and cause of poor performance at wheel set, truck,
`freight car or train level.
`
`BACKGROUND OF THE INVENTION
`
`2
`to that provided by wayside monitors, wiring, complexity and
`costs increase the investment required to monitor the cars.
`
`SUMMARY AND OBJECTS OF THE
`INVENTION
`
`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
`10 and provide both regular assurance of proper performance
`and, as necessary, warning ofimpending or actual failure in a
`timely and useful manner to the operators and owners of the
`train whereof if forms a part.
`It is a further objective of this invention that the perfor-
`15 mance of the railcar and its components could be combined
`with operating data from the locomotive to provide a com(cid:173)
`plete train monitoring system.
`It is a further objective of this invention to provide such
`functionality with minimal recourse to making wired electri-
`20 cal 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.
`It is a further objective of this invention that the compo-
`25 nents can be inserted or removed for inspection and repair or
`replaced during normal maintenance work on the railcars.
`It is a further objective of this invention to provide means
`for the timely analysis of measurements made during opera(cid:173)
`tion of the train so that the information about performance or
`30 failure can be sent in a concise manner so that there is no need
`for detailed measurements to be transmitted.
`It is a further objective of this invention that the messages
`sent about performance or failure contain sufficient informa(cid:173)
`tion that the exact location on the train of the item or items in
`35 question can be unequivocally determined, and that the loca(cid:173)
`tion of the train, or indeed of the freight car can be reported,
`should that information be available.
`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 inter(cid:173)
`ference between the successive (adjacent) cars in a train or
`from other equipment operating in the same band of frequen(cid:173)
`cies.
`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 description
`which follows features a freight car with two trucks ( or
`bogies ), it is applicable to almost any configuration with more
`50 or less trucks or axles.
`
`40
`
`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 infrastructure and lead
`to derailments) as soon as their performance becomes unac(cid:173)
`ceptable. There is also a need to increase average train speed
`by
`improving high speed performance 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 regu(cid:173)
`lation to improve safety, the railroad industry needs new ways
`to monitor the performance of trains, cars and railcar trucks.
`Some of the performance criteria that need to be monitored
`include roller bearing condition and temperature, roller bear(cid:173)
`ing adapter displacement, wheel condition, truck hunting/
`warp/binding, brake status and performance, whether a par(cid:173)
`tial derailment has occurred and potentially problematic track
`condition. Since some of these performance 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 effective, 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 45
`system need to be able to deal with a very large address a very
`large number of potential devices.
`One approach widely adopted in North America is to use
`wayside defect detectors at fixed locations throughout the
`railroad network. Detectors measuring bearing temperature
`(hotbox detectors) are common, while other wayside detec(cid:173)
`tors 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 55
`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 perfor(cid:173)
`mance is needed.
`Another approach to railcar performance monitoring has
`been to use on-board instrumentation. One such prominent
`system has been developed for the Federal Railroad Admin(cid:173)
`istration. In this and other similar systems, a number ofinstru(cid:173)
`ments on different areas of a freight car are used to make 65
`discrete measurements before being communicated to a cen(cid:173)
`tral hub on the freight car. While providing a superior solution
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIGS. 1-3 are schematic views showing the arrangement of
`components suited for use in carrying out the objectives of the
`present invention;
`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
`FIGS. 5-7 are schematic views illustrating alternative con(cid:173)
`figurations of elements of the invention.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENTS
`
`Turning now to FIGS. 1, 2 and 4, trucks 1, shown diagram(cid:173)
`matically, each carry two axles 2 each with two wheels 3. The
`
`60
`
`
`Page 6 of 14
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`

`

`US 7,688,218 B2
`
`3
`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.
`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 sidewalls 14 of each pedestal jaw along with
`a roof section 15 combine to form a pedestal jaw opening.
`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 comers
`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 tum 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.
`Referring further to FIG. 2, the pads 4 are seated on the
`upper rectangular surface of the bearing adapter. Each bear(cid:173)
`ing 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.
`FIG. 3 shows, in schematic form, an adapter pad 16 modi(cid:173)
`fied to carry out the objectives of the present invention. The
`pad contains a plurality of sensors 5 which are preferably
`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 por(cid:173)
`tion 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 associ(cid:173)
`ated 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 45
`to the analog to digital conversion circuit unit and the micro(cid:173)
`processor 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 50
`delivering sufficient voltage and having sufficient energy
`storage capacity so that when turned on periodically and
`briefly, as described hereinafter, the pad can be functional for
`several years, consistent with the normal service life of the
`bearing components used in the trucks.
`Alternatively, the power source may consist of an energy
`scavenging device which supplies energy to a rechargeable
`battery or capacitor. A strain generated electrical 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 60
`the truck and most preferably on the extension to the pad so as
`to avoid the need for electric wiring between relatively mov(cid:173)
`able car parts.
`FIGS. 1-3 further illustrate a railroad freight car 22 having
`trucks 1 with pads 16 with their associated sensors and control 65
`and communication circuit units 19 and 20. In the example
`described, each truck carries four pads 16 ( one for each bear-
`
`4
`ing) each having a power source 18, control circuit unit 19 and
`a communications unit 20, preferably comprising a radio
`transmitter/receiver.
`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 com(cid:173)
`municate 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
`10 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 circumstances
`and for some car types, the data control unit and the commu-
`15 nications device may be contiguous.
`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 con(cid:173)
`tinuous functionality. Communications device 24 serves to
`20 link the railcar either directly to the locomotive drawing the
`train so that the engineer or other crew personnel have imme(cid:173)
`diate 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
`25 equipment to monitoring stations as desired by the user. In the
`event that wired communication from the locomotive is avail(cid:173)
`able 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
`30 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.
`Also shown in FIG. 1 is a hand-held unit 23b containing a
`microprocessor and the radio for communication with the
`35 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 commu(cid:173)
`nications unit 23 for communication to take place. This
`40 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.
`Although the use of a radio for making the communication
`by the registrar is preferred, direct electrical contact could be
`employed. However, because of the harsh environmental con(cid:173)
`ditions 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 necessary. The use of the registrar in
`carrying out the functions of the invention will be described
`further below.
`At this point, it should be noted that a feature of the inven(cid:173)
`tion is to facilitate ascertaining the address for radio commu(cid:173)
`nication at the time of installation of a pad or during replace-
`55 ment of a pad or a data control unit. For this purpose, as an
`alternative to radio communication, a radio frequency iden(cid:173)
`tification (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.
`While the antennae shown in FIGS. 1 and 3 are schemati(cid:173)
`cally 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.
`Likewise, in place of battery power for the instrumented
`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
`
`
`Page 7 of 14
`
`

`

`US 7,688,218 B2
`
`5
`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.
`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 stan(cid:173)
`dard of which the ZigBee sensor network systems is exem(cid:173)
`plary. The power levels are low and range is limited but all that
`is required is generally the ability to communicate 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 15
`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 trans(cid:173)
`mission is that wiring on the trucks and wiring from trucks to 20
`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.
`Means for wireless communication based on the IEEE 25
`standard are available and adaptable to allow the instru(cid:173)
`mented 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 communication unit is 30
`informed of the configuration providing thereby a multi-hop
`means oflinking the network together. Radios used in carry(cid:173)
`ing out the above aspects of the invention are intended to be
`operated intermittently at low power. Several frequency
`bands are acceptable in various parts of the world. A suitable 35
`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 contain
`several sensors for measurement of dynamic and static verti-
`cal 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 45
`attached rigidly to the wheels, and subject to track irregulari(cid:173)
`ties, 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.
`With reference again to FIGS. 1-3, in operation, the micro(cid:173)
`processor 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 55
`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 60
`further intelligence but increase power consumption.
`The periodicities of sampling and of reporting are con(cid:173)
`trolled 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 65
`the radio which it controls and send an appropriate message
`via the radio to the data control unit 23. An example of such
`
`6
`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 nor(cid:173)
`mally result in its being in a low powered state most of the
`time.
`The data control unit 23 is intended to serve several pur(cid:173)
`poses. It coordinates the timing of the cyclic testing per-
`10 formed by the instrumented pad microprocessor and the tim(cid:173)
`ing 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 derail-
`ment. It passes on information from the communications
`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 infor-
`mation may also be used to inhibit sensor checks when no
`purpose is thereby to be served in order to preserve energy
`usage.
`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 commu(cid:173)
`nications 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.
`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 turn,
`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.
`Alternative configurations for the monitoring system
`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.
`In the embodiment of FIG. 6, all of the pads 16 from one
`truck communicate with a single microprocessor and radio
`50 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 compu(cid:173)
`tational services performed in the microprocessor unit on the
`truck may be somewhat different from those in the micropro(cid:173)
`cessor unit of FIG. 5. In this embodiment, all the analog to
`digital conversion functions are performed in the micropro-
`cessor and any inference functions performed there make
`assessments for all sensors for all pads on the truck.
`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 micropro(cid:173)
`cessor 28 on the particular pad. Those microprocessors can
`then communicate with the single data handling unit 25 on the
`truck and hence to the data control unit 23. As in the configu-
`ration 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.
`
`40
`
`
`Page 8 of 14
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`

`

`US 7,688,218 B2
`
`7
`Other options include standard CANBus communication
`schemes where wired links are used. In addition, CANBus or
`other standards may be implemented in the event of wide
`scale implementation of electronically controlled pneumatic
`brakes potentially providing other options for communica(cid:173)
`tion schemes.
`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 communication
`along passenger trains, Rail Transit Vehicle Interface Stan(cid:173)
`dard, IEEE1473-199 would be applicable.
`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 likelihood that trains
`will be reconfigured with freight cars possibly being removed
`or shuffled or the train being pulled by a locomotive at its 20
`opposite end. Any such network depending upon pad-to-pad
`links from car-to-car would require reconfiguration of the
`train in marshalling yards.
`As indicated above, it is a feature of the invention to have
`appropriate means of addressing and identifying each and 25
`every instrumented pad in railcars used in the system. Further,
`it is necessary that the instrumented pads on trucks on adja(cid:173)
`cent 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 30
`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 pro bl ems to report, it is important that
`the system provide assurance that it is still functioning prop(cid:173)
`erly. The preferred system described herein uses messages 35
`initiated by the instrumented pads for this purpose. The alter(cid:173)
`native 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 40
`they are allowed to send messages based on their own timing
`with the requirement that the data control units is always in a
`receiving mode.
`The instrumented pads which are to be mutually interop(cid:173)
`erable with the corresponding data control units must all use 45
`matching frequencies. The aforementioned IEEE802.15.4
`standard designates frequencies or channels in each fre(cid:173)
`quency 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 50
`8-bit bytes of data wherein each byte has a preassigned mean(cid:173)
`ing. 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 55
`receivers and their controlling microprocessors 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 con- 60
`trol. They can act appropriately on messages 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 65
`pads on its own freight car. Instrumented pads have to be able
`to recognize messages from their own data control unit and
`
`8
`both have to be ab