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7.Spread R i m :(See Figure 7)The WheelFax can detect a spread rim if the wheel hascertain types of cracks in the tread surface.8.Thin R i m ;3/4 inch or less for all wheels except 28, 36, 38inch wheels which are 7/8 inch or less.A thin rim will not be detected by the WheelFax because itcannot establish the inner radius of the rim.9.(See Figure 8) When the shell or spall is 3/4inch in length and in width or larger and aremore or less continuous around the peripheryof the wheel or one inch or more in lengthand width.The WheelFax system can detect a shelled area on a tread.The system cannot determine the severity of the shelling; and,therefore, may alarm on serviceable wheels that have less thanthe condemnable amount of tread shelling.10.Shelled T r e a d ;Built-up Tr ea d :Metal built-up 1/8 inch or more on tread(See Figure 9).The WheelFax system can detect built-up. tread. As in wheelshelling, it cannot measure the severity of this tread defect andtherefore could alarm on serviceable wheels.11.Grooved Tr ea d : One or more grooves worn to a depth of 1/8inch or more (See Figure 10).The WheelFax system will not detect a grooved tread for thesame reasons as for the thin flange.12.Thermal Cracks:Certain types of cracks in tread, flange orplate of any length (See Figure 11).The WheelFax system can detect cracks in the tread area butthe length and depth of these cracks must be at least 1/40inch. It can also detect' cracks in the flange and the rim faces,both back and front. Total penetration of the surface wave isapproximately 3/8 J.nch below the tread surface. System

tFIGURE 7.FIGURE 8.SPREAD RIMSHELLED WHEEL18

iFIGURE 9.FIGURE 10.BUILT-UP TREADGROOVED TREAD19

iFIGURE 11.THERMAL CRACKS20

i,sensitivities are typically increased to allow detection ofthermal cracks other than ones found in the wheel treadsurface. When this is done the false alarm rate increases.13-Cracked or Broken P l a t e ;(See Figure 12)The WheelFax system will not detect a wheel with a crackedplate unless the crack originates from the plate and haspropagated through the rim/tread surfaces.14.Holes in P l a t e :(See Figure 13)The WheelFax system will not detect any defects in the wheelplate area.15.Loose W h e e l :Wheel showing evidence of movement on thewheel seat or oil seepage on the back plate.The WheelFax system will not detect a loose wheel.16.Overheated W h e e l :Due to stuck dragging brakes showing"reddish brown" or "blue" discolorationfour inches from the front or badk faceof rim into the plate.The WheelFax system will not detect a wheel that has beenoverheated.17.Wrong Diameter W h e e l ;Wheel not standard to car.The WheelFax system has optional equipment to measure wheeldiameter. However, the optional equipment cannot determinewhether the wheel under test is the right diameter.18.Out-of-Gauge W h e e l s :(See Figure 14)The WheelFax system will not detect out-of-gauge wheels.19 Remove On-Sight, Prohibited in Interchange:The WheelFax cannot detect these wheels unless the wheelshave detectable flaws or defects located on their treads orflanges.21

N toFIGURE 12CRACKED ORBROKEN PLATE

FIGURE 13HOLE IN PLATE

i Wheels manufactured prior to 1965will be out of gauge if the backto-back dimension is less than52-15/16 inches.F-IGURE 14.WHEEL GAUGE STANDARD23

20.Scrape, Dent or Gouge: Wheels having a scrape, dent orgouge anywhere in the wheel surfacemore than one-eighth inch deep.The WheelFax can detect a Scrape, dent or gouge only whenlocated in the tread or flange of a wheel.21.Slid F l a t :Flat two inches or more in length or two or moreadjoining spots each 1 1/2" or over in length.The WheelFax can detect a wheel flat. However, the WheelFaxcannot determine the severity of wheel flats; and therefore mayalarm on serviceable wheels.*24

t3.HISTORY OF THE WHEELFAX SYSTEMBackground on WheelFax SystemsScanning System, Inc. manufactured one prototype and threecomplete WheelFax systems in the mid-1970's. They delivered theprototype system to the Atchison, Topeka and Santa Fe Railroad(ATSF), and one complete system each to the Canadian PacificRailroad (CP), the Florida East Coast Railroad (FEC) and theFederal Railroad Administration (FRA). Currently, the FEC systemhas the only operational system in service.Atchison, Topeka and Santa Fe SystemThis prototype WheelFax system was installed in ATSF'sArgentine yard in June 1973. The prototype system only tested,wheels on one side of a passing train.The prototype system was leased to the ATSF with an optionto buy. The option was never exercised and the system wasultimately returned to the manufacturer. The system proveddifficult to maintain during the evaluation phase; and had longperiods of down time.When the WheelFax system was operating it generated manyfalse alarms because it was sensitive to tread flaws that werenot condemnable defects. A false alarm is defined as theidentification of a serviceable wheel as defective. Ultimately,the system was returned to the manufacturer.Canadian Pacific SystemThe WheelFax purchased by the CP was the first completesystem, for both left and right rails, delivered by ScanningSystems, Inc. The system was procured for a developmental wheeldefect detection project and was installed in the St. Luc Yardnear Montreal, Canada. The system was ready for field testing inthe latter part of 1976. The test phase was approximately twoyears, during which time the system did show the capability ofdetecting wheel thermal crack defects in the tread and flange of25

IWheels.However, the system was also prone to failures andrequired considerable maintenance to keep it operational.In addition to maintenance difficulties, the CP WheelFax hadan unacceptable number of false alarms. All wheels identified asdefective by the WheelFax System require further inspection byrailroad personnel. This takes manpower and equipment to cutcars for manual inspection. The WheelFax System can notdistinguish between thermal tread cracks which are not acceptableand some tread flaws such as shelling, build-up or small slidflats which are acceptable depending on their magnitudes.Unfortunately, these acceptable flaws are often found on therunning surfaces of a railroad wheel.In the process of evaluating the WheelFax System, the CPmade several modifications which include the following: Additional electronic circuitry was added to recordthe WheelFax logic decisions to aid in interpretingthe data.Floating d.c. power supplies for various components(i.e., paint system, search unit heaters) to reducenoise.A train overspeed circuit to measure rail vehiclespeeds over the search units. If the speed of thevehicle was greater than the maximum speed allowed,the WheelFax would not be activated.Modifications were made to calibration proceduresdue to the large number of alarms. The CP stoppedusing their rail test car that had wheels withmachined flaws and started using a statisticalapproach to set the overall system sensitivity andreduce the number of wheel alarms.The CP discontinued their evaluation program and in 1981they sold their WheelFax system to the Union Pacific Railroad(UP). The UP is having the system refurbished by its inventorand developer. .26

1'Federal Railroad Administration SystemAnother complete WheelFax system was delivered to theFederal Railroad Administration in October 1976. This unit hasbeen installed at three different locations at the TransportationTest Center in Pueblo, CO. The first site was in the activetrack at the Facility for Accelerated Service Testing (FAST).Eighty test runs at this site were carried out for acceptance ofthe system. The second site was on the FAST by-pass track.Testing at this location was done to collect data to be used toevaluate the system design of proposed additions (i.e., wheelsize classification and high flange detection) to the system.The third installation site was the Wayside Research TestFacility where the WheelFax system with the wheel size and highflange detectors could be tested and evaluated along with theother detection systems such as the Acoustic Cracked PlateDetector, Loose Wheel and Broken Flange Detector, Hot Box and HotWheel Detector, etc.The FRA unit has the following options: Wheel size detector; High flange detector;Data transmission to remote location;Bi-directional paint system;Track heaters; andAir conditioned track-side equipment building.The FRA WheelFax system was evaluated while located at theTransportation Test Center (TTC). There were numerous testsusing rail vehicles with machined flaws in their wheels. Asignificant portion of these evaluation tests were devoted toestablishing system sensitivity thresholds. During these testsequences the sensitivity thresholds w e r e -varied. Determiningthese values are crucial because they directly affect the overallsystem accuracy. If the thresholds are set too high, there couldbe many faulty wheels that would go undetected; and if they areset too low, there may be an unacceptable number of falsealarms.27

tA preliminary WheelFax report generated by the Transporta tion System Center (TSC) provides an evaluation of data taken atTTC. This report concludes that'the WheelFax system had mainte nance difficulties, but it did consistently detect the machinedflaws in the wheels of rail vehicles that were operated over thein-track search units. Also, the WheelFax system was more re peatable in detecting man-made flaws located on the center of thetread of the wheel versus those found on the extremes of thetread, front and back face of the wheel rim and on the wheelflange.Florida East Coast WheelFax SystemIn May 1974, the management of the Florida East CoastRailroad approved the purchase of a WheelFax system. The FECprovided labor and materials to support the manufacturer duringinstallation and checkout of the system.Since the FEC system is currently the only in-service WheelFax unit, a visit was made to their Jacksonville, FL installationduring which a detailed analysis of their operation and mainte nance procedures was performed. This analysis can be found inSection 4, WheelFax Operations on the Florida East Coast Railroad(FEC).In general, the FEC experienced and solved difficulties inthe following areas: Boots for the search unit required daily replace ment. An adjustment in boot height above the railfrom 1/2" to 7/16” solved this problem. Also, theboots were redesigned to improve their longevity.The container tank that holds the WheelFax couplingfluid was corroding and contaminating the fluid.The contaminated fluid would then clog the couplantspray nozzles. With the nozzles clogged, there isinsufficient coupling fluid sprayed onto the wheeltread surface for the WheelFax to operateproperly. With this condition, most wheelstraveling over the WheelFax register as "notest." The solution was to use a fiberglass ratherthan a metal storage tank.The WheelFax system uses eight strain gauge wheeldetectors attached to the web of the rail. Due to28

)» failures, four of these strain gauge bridges werereplaced with magnetic wheel detectors.FEC developed necessary'documentation.FEC had to procure additional hardware for thesystem.The internal temperature of the main control centeris critical. This problem was solved by theinstallation of air conditioning.FEC had to develop their own calibration andmaintenance schedules.29

1,4.WHEELFAX OPERATIONS ON THE FLORIDA EAST COAST RAILROAD (FEC)On the FEC the Communications and Signals (C&S) Departmentmaintains the WheelFax electronics and they are responsible forits calibration. The Maintenance of Way Department under thedirection of C&S personnel maintains the track structure, i.e.,ties, joint bar tightening, etc.A signal maintainer checks the unit every morning; thismaintainer can do only limited maintenance such as replacingsearch unit boots or unclogging spray nozzles. Also, calibrationis done once a week by an assistant signal supervisor. Due tothe FEC operations, this calibration is split between theafternoon of one day and the morning of the next. If no systemproblems are encountered, the calibration can be completed easilyin one afternoon (2 to 3 hours). That night or early the nextmorning, a yard engine crew picks up the calibration vehiclewhich is a gondola with defective wheels and operates thisconsist over the WheelFax search units. On the morning of thesecond day, the Assistant Signal Supervisor analyzes video datarecorded from the previous night. The results of this analysisdetermines if the WheelFax system is operating properly. If itis not, the faulty unit(s) is repaired. After repairs have beenmade, the gondola test vehicle may or may not be used to verifysystem operations.As a minimum, approximately 14.5 man-hours per week are usedto maintain and calibrate the FEC WheelFax system. This assumesthat a signal maintainer spends about one hour per day checkingthe unit, the Assistant Signal Supervisor spends approximatelyeight hours a week at the site and the crew on the locomotive isinvolved for at least 45 minutes (2 crewmen) once a week. Ifthere are problems with the system, the required effort increasesabove this minimum.With respect to the electronics the C&S Department maintainsa complete set of spare printed circut (PC) boards. Their normalmaintenance procedure is to replace defective boards and returnthese PC boards to their supplier for repair.30

1The FEC fabricated its own calibration wheel sets. Eachwheel has a single saw cut made by a rail saw. The depth ofthese cuts vary from ones just through the flange to others thatpass through the flange, the tread, the rim and into the plate ofthe wheel. The two wheels on a wheel axle set do not necessarilyhave matching defects. The saw cuts must be cleaned occasionallyor they will eventually become clogged with brake shoe dust, rustor other debris found along the railroad right-of-way. Thesewheel sets are mounted on trucks that are placed under a gondolacar. This gondola is used as a calibration vehicle which isoperated over the in-track search units to verify that the systemis calibrated and working properly. The FEC found that when thecalibration vehicle is operated over the WheelFax search unitsand the saw cuts in the wheels are clogged, the response of theWheelFax system is degraded.At the present sensitivity thresholds set by the FEC, theWheelFax typically does not detect the man-made saw cuts in theflange of the test wheels. The system reliably detects all ofthe other saw cuts.Sensitivity thresholds currently used by FEC were derivedempirically through field testing. During the initial test phaseof the system, wheels that were rejected by the WheelFax werethoroughly tested using the WheelFax Junior (a portable, handheld version of the WheelFax) and also were machined to detectany hidden defects. Therefore, FEC derived their desiredsensitivity threshold values by setting them such that the wheelrejection rate versus actual defects found was acceptable. Asimilar technique was used by the Canadian Pacific except theyultimately discontinued using the calibration test vehicle.It appears that alarms from the in-track WheelFax unitaccount for only some of the total wheels replaced by the FEC.The majority of .defective wheels are found during incoming oroutgoing visual inspections. The wheels rejected are due mainlyto flange defects, i.e., high or thin. The remaining wheels arerejected due to discoloration bands (heat) on the wheel plate,thin rims, shelling, thermal cracks, etc.31

j1 The strip chart recorder for the WheelFax is located in theCar Foreman's office remote from the in-track system. Thisrecorder displays an identification mark .for each wheel as itpasses over the WheelFax search units. Also, at eachidentification mark there is one of four indications made by theWheelFax decision electronics. The wheel was tested.The wheel was not tested.Alarm.Calamity alarm.As described in Section 2, Introduction, a track side paintsystem marks defective wheels.Car inspectors must rely on seeing the painted wheel foridentification. When the car inspector sees a wheel that hasbeen painted the inspector examines the tread of the wheel. Ifthere are non-condemnable flaws in the tread of the wheel thatcould possibly have caused the WheelFax to alarm, the wheel isleft in service. If there are no visible flaws in the tread ofthe wheel, the wheel is inspected using the WheelFax Junior. Ifthe WheelFax Junior detects an external defect or internal flawthe wheel is replaced; if not, the wheel is left in service.32

t5.ACCIDENT/COST ANALYSISFor the years 1976 through 1980 there were an average of 378accidents per year attributed to wheel failures (see Table 1).The average cost to the railroad industry due to these accidentswas approximately 18.4 million/year. Additional costs (societalcosts) as a result of these accidents other than damage torailroad rolling stock and fixed equipment and lading loss couldbe as much as 10 times greater adding as much as 184million/year to the average accident costs.The approximate annual cost of accidents to the railroadindustry is estimated to be: 18.4M 184M 202.4MDuring the period 1976-1980, there were 1,890 wheel failuresthat resulted in accidents. Given that the WheelFax system mayd e t e c t To of the 21 wheel defects detailed in the FieldManual of the AAR Interchange Rules and the accident data shownin Table 1, in-place systems may have been able to detect 181broken flange, 216 broken rim and 66 damaged flange or thread,thermal/flat for a total of 463 accidents due to wheelfailures. Thus the WheelFax may have detected approximately 24percent of the wheel defects which led to accidents during the1976-1980 period.The railroad industry could have potentially saved 24percent of their estimated annual losses or 48.6M per year,assuming total efficiency of the WheelFax system, no falsealarms, and the system being in-place at major classificationyards across the country.Although this would appear to be a significant annual costsavings to the industry, there are problems which might limitWhee l F a x ’s applicability at this time such as:33

uTABLE 1.SUMMARY OF WHEEL ACCIDENT/COST DATA, 1976-1980FROM FRA ACCIDENT/INCIDENT BULLETINSYEARSPercentTotalAccident Cause19761977“Broken Flange“Broken RimBroken Plate1Broken HubWorn Flange or Tread“Damaged Flange orTread, Thermal/FlatLoose WheelCause Code Not 90100DerailmentsCollisionsOther40139396423 2773.89,7403.58,4513-950,0783-8 15.5M 37,500 17.8M 43,600 19.4M 44,500 22.5M 66,600 16.6M 56,300 9 1 .8M 48,600TOTAL RR ACCIDENTSPercent Due toWheel FailuresTOTAL Indicate defects which may be detected by the WheelFax system.9.611.412.1

1 The WheelFax system will not operate reliably atvehicle speeds greater than 20 mph.Systems would be required at rail yards throughoutthe U.S. to detect even 24 percent of the wheeldefects which are potential failures and will causea c ci dents.Operational analysis of the system has shown thatconsiderable time and manpower is required forsystem operation and maintenance.The system could create a virtual standstill of therailroad industry, especially if it were installedat the exit track, if there was a significantnumber of false alarms as yard personnel andequipment would be tied-up to cut out flaggedvehicles and inspect the suspect wheels.35

\6.CONCLUSIONS AND RECOMMENDATIONystals may not haveenough time to function properly because the wheel was not on the12

FIGURE 5.SIGNAL PATHS FOR ULTRASONIC SURFACE WAVES13

i* search unit boot for a sufficient period of time.mph speed limitation.Hence the 20The recorder which makes a record of the train wheels testedmay be located at a convenient remote location. The output ofthe control center for each of the two rail search units operatesa pen which deflects in two directions. The resultant patternenables rapid identification of a particular wheel.Wheel DefectsRule 41 Section A of the AAR field manual lists 21 differentwheel defects that would require a wheel to be condemned. Out ofthese 21 defects, 11 are not detectable and 10 are detectable bythe WheelFax system. Of the 10 detectable defects, four canexist on a serviceable wheel provided the severity of each areless than the limits defined in the AAR manual. In its presentconfiguration, the WheelFax system cannot distinguish betweendefect types and cannot measure defect severity. Therefore, theWheelFax system would be expected to produce many false alarms onwheels that are serviceable.The following provide brief explanations of each defectlisted in the Field Manual of the AAR Interchange Rules and whythe WheelFax may or may not detect each.1.Thin F l a n g e :15/16 inch thick or less.Due to crystal alignment, the ultrasonic energy injectedinto the wheel tread produces a surface wave that travelsparallel to the wheel flange. Therefore, due to the geometry ofthe wheel, there is no wheel flange surface to reflect the energyto the receiver. Therefore, the WheelFax system will not detecta thin flange.2.Vertical F l a n g e :Flat vertical surface extending one inch ormore' from tread.The WheelFax system will not detect this flaw for the samereasons as stated for thin flange.14

t3.HighFlange;Height is 1 1/2 inches or more above theapproximate centerline of tread.The WheelFax system has an optional high flange detector.The FRA WheelFax unit was procured with this option. However,there are insufficient data to establish whether this option evermet its specifications. None of the other WheelFax units hav,eused this concept and because of electrical problems it may bedifficult to implement.4.Cracked or Broken Flange:Any length. Chipped flange mustexceed 1 1/2 inches in length bythe width and not merely a flakingof the surface.The WheelFax can detect both of these defects. The FRA hasdone considerable field testing in these areas; and it appearsthat when the system is adjusted to detect cracks in the flangearea false alarm rates also increase. In addition, the WheelFaxcannot measure defect severity and, therefore, can alarm on anon-condemnable chipped flange.5.Cracked or Broken R i m :The WheelFax system can detect both of; these defects. Witha cracked or broken rim, a portion of the ultrasonic energy thattravels around the wheel should be reflected at the crack andwill travel back towards the receiver. When the WheelFax detectsa reflected ultrasonic pulse the system will generate an alarm. 66.Shattered R i m :(See Figure 6)The WheelFax system can detect this defect as it doescracked or broken rims.15

1FIGURE 6.SHATTERED RIM16

7.Spread R i m :(See Figure 7)The WheelFax can detect a spread rim if the wheel hascertain types of cracks in the tread surface.8.Thin R i m ;3/4 inch or less for all wheels except 28, 36, 38inch wheels which are 7/8 inch or less.A thin rim will not be detected by the WheelFax because itcannot establish the inner radius of the rim.9.(See Figure 8) When the shell or spall is 3/4inch in length and in width or larger and aremore or less continuous around the peripheryof the wheel or one inch or more in lengthand width.The WheelFax system can detect a shelled area on a tread.The system cannot determine the severity of the shelling; and,therefore, may alarm on serviceable wheels that have less thanthe condemnable amount of tread shelling.10.Shel

delivered to the Canadian Pacific Railroad (CP), the Federal Railroad Administration and the Florida East Coast Railroad. (FEC). The FEC system is the only unit currently in service. The CP recently sold their unit to the Union Pacific Railroad. This unit is currently being restored to

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