UIC Leaflet 865-2: The Standard for High-Strength Railway Sleeper Screws

What is UIC Leaflet 865-2?

UIC Leaflet 865-2 is a specialized technical document titled “Technical specification for the supply of steel sleeper screws.” In the rail industry, sleeper screws (also known as tire-fonds or lag bolts) are the critical components that anchor the rail fastening system to wooden or composite sleepers.

Unlike standard construction screws, railway sleeper screws must withstand extreme cyclic loading, intense vibration, and significant lateral resistance forces generated by passing trains. UIC 865-2 ensures that these fasteners possess the necessary material toughness and dimensional precision to maintain gauge retention over decades of service in the Permanent Way (P-Way).

Technical Specifications and Material Quality

The leaflet establishes the “Technical Delivery Conditions,” which govern the entire manufacturing process. Key requirements include:

• Material Composition: Typically specifies high-quality carbon steel with precise control over sulfur and phosphorus content to prevent brittleness.
• Manufacturing Method: Screws must generally be hot-forged or cold-formed with rolled threads. Rolled threads are mandatory as they provide superior fatigue resistance compared to cut threads.
• Mechanical Properties: Defines minimum tensile strength and elongation limits. The screws must be capable of being tightened to high torque levels without stripping the head or snapping the shank.
• Surface Protection: Standards for galvanization or bitumen coating to protect against corrosion, especially in wet or saline environments.

Geometric and Functional Standards

UIC 865-2 ensures that the screw geometry is optimized for the specific wood density of railway sleepers. The pitch and depth of the thread are designed to maximize “pull-out strength,” ensuring the rail remains firmly seated even under the dynamic “wave” motion of the rail during high-speed passage.

Comparison: UIC 865-2 vs. Standard Industrial Fasteners

Transition to European Norms (EN)

Modern rail procurement in Europe has largely transitioned from UIC 865-2 to the EN 13481 series (Fastening systems for sleepers). However, UIC 865-2 remains the primary reference in many international markets and for maintenance of existing tracks where “like-for-like” replacement of legacy tire-fonds is required.