NR NR/L3/TRK/055/U5 ISSUE 1 PDF

This procedure applies to the defects listed below in all pearlitic rails as far as coupling conditions allow, see table 1.

• Squats

• Wheelburns

• Arc weld head repairs

• Tache Ovales

• Severe/Heavy rolling contact fatigue (R.C.F) in machined rails between the point where RSU-RTS can no longer maintain a rail bottom signal towards the toe of the switch as far as coupling conditions allow.

• Aluminothermic weld (ATW) defects (following a signal response >50% FSH from the U15 procedure).

Purpose

This ultrasonic procedure is used to assess the horizontal length and vertical depth of transverse defects within the railhead; inspect MMA and semi-automatic FCAW welds; position tache oval defects accurately, assess heavy or severe RCF on planed sections of rail where U15 coupling cannot be achieved and determine the depth of discontinuities detected by other approved techniques.

This procedure measures the size of each respective defect to set the MAC.