EN 13231-2: Railway Applications – Track – Acceptance of Works – Part 2: Acceptance of Rail Reprofiling in Track

What is EN 13231-2?

EN 13231-2 is a key European quality standard titled “Railway applications – Track – Acceptance of works – Part 2: Acceptance of reprofiling rails in plain line, switches, crossings and expansion devices.” It serves as the primary benchmark for Infrastructure Management to verify that contractors have correctly performed rail maintenance tasks such as Rail Grinding or milling.

The standard is designed to ensure that the reprofiled rail meets specific geometric and surface quality requirements. Proper adherence to these tolerances is essential for reducing noise, vibration, and the acceleration of Rolling Contact Fatigue (RCF).

Key Technical Parameters

The acceptance of works under EN 13231-2 is based on three main technical categories. If a reprofiled rail exceeds these limits, it is considered non-compliant and may require rework:

• Longitudinal Profile: This measures the “waviness” of the rail along its length. The standard defines different wavelength ranges (e.g., 10–30 mm, 30–100 mm, etc.) and sets the maximum permissible peak-to-valley depth for each.
• Transverse Profile: This ensures the shape of the rail head matches the design template. Contractors use a “target profile” to ensure the contact point between the wheel and rail remains centered and stable.
• Surface Roughness ($R_a$): While geometry is vital, the microscopic texture of the rail is also regulated. Excessive Surface Roughness can lead to increased rolling noise and initial wear.

Acceptance Classes

The standard allows for different “Acceptance Classes” depending on the speed and traffic density of the line. A high-speed line will require much tighter tolerances than a freight-only branch line. These classes dictate:

• The percentage of the measured track that must meet the specific tolerances (usually 90% or higher).
• The methodology for measurement, often requiring calibrated digital profile loggers or “Mini-Prof” devices.

Maintenance Impact

By enforcing EN 13231-2, railways can extend their Maintenance Intervals. Removing surface defects like “squats” or “corrugation” through reprofiling prevents these minor flaws from developing into deep cracks that would necessitate premature rail replacement. This is a core component of a modern Track Quality strategy.

Comparison: Longitudinal Profile Wavelength Tolerances