Track geometry modules - TQM calibration

TQM track geometry measurement accuracy depends on accurate, computer controlled system calibration related to the ambient temperature. In TQM solution it can be carried out both in a stable office environment or out on the track

Calibration tools, Certified Blocks and Calibration procedures are supplied to customer with the TQM delivery. Calibration of a TQM means calibration of each TQM track geometry measuring module separately, for which only two operations are carried out: Factor Calibration and Zero Calibration

Track geometry module Factor Calibration (Volts to Millimeters). Three different sizes of Certified Blocks (CB) are used to convert sensor voltage output into millimeters. Two Calibration Factors are calculated from the Main and Control Calibration. Factor Difference (m1 - m2) is subsequently validated against calibration criteria and it is saved or rejected accordingly

Track geometry module Zero Calibration Previously calibrated Factor is used to calculate a constant determining Zero position for calibrated module. Zero calibrating mechanism is similar to the Factor Calibration but readings are taken from track geometry module specific positions against TQM Zero Calibration tools. As in the above, Zero difference from the Main and Control Calibration is validated against Calibration Criteria then Saved or Rejected accordingly

Inclinometer Temparature Calibration. Two different approaches are used in TQM solution for track geometry measuring modules equipped with inclinometers:
1. Appropriate Calibration parameters are used for various temperatures (requires relevant temperature related parameter to be inputed prior each survey
2. Stable temperature environment is secured around the sensor box (one parameter for all ambient temperatures)