Rail Break Study

Root cause analysis of broken and defective rails.

Synopsis

The objective of the investigation was to inspect and classify broken and defective rail samples from a wide geographical spread across the client’s rail network and to identify defect development and failure trends over a specified time period. The key questions to address were to determine the extent and root causes of defect development. Metallurgical expertise and extensive experience of rail defect investigations were needed, along with appropriate laboratory facilities, to solve the problem. Corus was able to service these requirements.

Key Client Issues

There was little understanding of the root causes and propagation of rail defects leading to:

• Broken and / or defective rails in track
• Potentially increased passenger safety risks
• Disruption of services
• Additional costs of rail replacement

Solutions

We undertook visual inspections and detailed metallurgical investigations to identify the root cause of broken rails. Specialist laboratory examination included:

• Non destructive testing, including ultrasonic testing and magnetic particle inspection
• Metallurgical and microscopic examination

The results yielded:

• Details of identified metallurgical root causes of failure and recommendations regarding relevant control strategies
• Analysis of the correlations between rail defect type/location and other track-related information, e.g. geometry
• Details of trends seen on a regional and national basis
• Classification of samples to the client’s in-house standard for broken rail root cause analysis

Client Benefits

The classification of investigated samples gave the client:

• An understanding of the identified failures and their root causes
• Recommendations for long-term maintenance plans

This in turn helped the client to develop control strategies to extend rail life.