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📊 Understanding Chart Recorder Misfits

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Our chart recorders automatically check each assembly (like mounting a wheel) to make sure everything fits and functions correctly. If something doesn’t look right, the system flags it as a “misfit” based on the settings defined by your administrator using Shop Manager. Refer to the Shop Manager user guide section on Editing an assembly configuration (User Guides — AIC Rail) for more information.

✅ What’s a “Good” Chart?

  • GoodPress (0) – Everything looks good. No issues detected.

🚨 Automatically Detected Misfits

These are issues the system can detect on its own:

🔧 Force-Related Issues

  • MinimumForceNotReached (2) – The minimum required force was not reached.
  • MaximumForceExceeded (1) – The maximum allowable force was exceeded. 
  • DropAfterMinForce (17) – The force dropped below the minimum after reaching the peak as defined by the AAR MSRP G-II 1.4.1.3.3.
  • DropoffExceedsLimit (19) – The force drop-off after the peak exceeded the acceptable limit.
  • MaximumSpikeExceeded (22) – The spike force exceeded the maximum allowed value. Typically, this would be for wheelsets with inboard bearings.
  • MinimumSpikeNotReached (23) – The spike force did not reach the minimum required value. Typically, this would be for wheelsets with inboard bearings.

📏 Distance-Related Issues

  • MinimumDistanceNotReached (4) – The minimum required distance was not achieved.
  • MaximumDistanceExceeded (5) – The maximum allowable distance was exceeded.
  • DistanceVariation (18) – The chart distance was inconsistent between the A and B sides by more than the specified tolerance.

📉 Graph Shape Issues

  • EntrySpike (7) – An entry spike was detected that was more than the allowed threshold as determined by the AAR’s MSRP GII rule1.4.1.3.4
  • PressureDip (8) – A drop in force greater than the acceptable amount was detected as defined by the AAR’s MSRP G-II Fig. 4.22.
  • BuildTonnageThru75Percent (14) – Force didn’t build up properly in the first 75% of the process as defined by the AAR’s MSRP G-II 1.4.1.3.2.
  • AbnormalGraph (15) – The force increased non-linearly as determined by an r-squared statistical algorithm. Sometimes this is referred to as an “ugly chart detector” or “graph exceeds r-squared limits”.
  • TemplateMisfit (16) – The force fell outside the expected template. Currently only two mounting templates are supported: The AAR wheel mounting template defined in MSRP G-II Fig. 4.20 and the template defined in EN13260. 

🛠️ Manually Selected Misfits

These need to be reviewed and selected by a technician in the Shop Manager system:

  • MaximumDropOffPressureExceeded (3) – Force dropped too much at the end.
  • BadRadial (6) – The radial runout measurement exceeded tolerance.
  • BadPlane (12) – The plane runout measurement exceeded tolerance.
  • TapeMismatch (9) – The tape size of the two wheels exceeds the threshold.
  • ComponentMismatch (10) – The component doesn’t match the expected setup.
  • Other (11) – Something went wrong, but the cause isn’t clear.
  • OutofGage (13) – The spacing between wheels is incorrect.
  • RamBackupError (20) – A mechanical error occurred during the process.
  • MaximumDeltaAreaExceeded (21) – The area under the force curve was too large.
  • SystemError (99) – A general system error occurred.

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