NR NR/BS/LI/057 ISSUE 1 PDF

Introduction

The principal objectives of grinding rail are as follows:

• To produce a regular and consistent running band on the crown of the rail.
• To impose and maintain a profile that reduces contact stresses on the gauge corner and shoulder of the rail.
• To remove localised misalignment at welds and other track features.
• To remove the fatigue damaged surface of the rail, which has or is likely to initiate rolling contact fatigue cracks.

The priorities for current train based grinding should be as follows until such time as grinding resources are available to control the initiation and early propagation of rolling contact fatigue.

• Rails with light or moderate RCF – to reach the target profile as quickly as possible.
• Rails with heavy or severe RCF – to reach the target profile as quickly as possible.
• Rail in a curve that has been previously re-railed due to rolling contact fatigue – to reach the target profile as quickly as possible.
• Rails with severe corrugation – to reduce peak-to-peak amplitude of the corrugation.

Grinding should be targeted so that the highest priority curves are ground approximately every 10 to15 EMGT and straight track every 25 to 30 EMGT of traffic.