Track geometry measurement errors

Certified Blocks: Select Gauges (CPD) Ltd imperial, tangsten carbide calibrated by Calmet Laboratory CB were used to assess TQM module Measuring Errors. Certified value to nominal: +/- 0.000005inch (+/-0.00013mm) in 20 deg Celsius.
Test results [mm] shown on the graphs below
 

Procedures: Twenty numbers of various sized Certified Blocks (CB) were used to test the full measuring range of each module. Readings were taken on different parts of the Measuring wheels. Errors were calculated from 20 independent measurements for each CB by reducing all readings to First Measurement and working out errors against the theoretical value. Only Maximum Errors from 20 independent differences to theoretical are shown on the graphs
 

TQM Track geometry errors derived in such way have mechanical and sensor compound built in, therefore, can give a good indication of the overall TQM accuracy, providing all necessary corrections relating to Temperature, Rigid Base and Zero position plus measuring wheel cleaning are taken care of