What is the primary difference between EN 13674-1 and EN 13674-2?

EN 13674-1 specifies the requirements for standard Vignole (flat-bottomed) rails used in plain, continuous track. EN 13674-2, however, deals specifically with the more complex and robust rails used to construct switches, crossings, and turnouts. These rails have stricter dimensional tolerances and often utilize higher-strength, heat-treated steel grades to withstand the increased dynamic loads at these locations.

Why are the hardness requirements for switch rails so important?

Hardness is a direct indicator of a rail's resistance to wear and plastic deformation. In a turnout, switch rails and crossing noses are subjected to very high contact stresses and impact forces as wheels are guided from one track to another. High hardness, typically achieved through heat treatment (like in grade R350HT), is essential to prevent rapid wear, material fatigue, and maintain the precise geometry required for safe operation.

Which steel grades are most common under EN 13674-2?

The most commonly specified steel grades include R260, which is a standard carbon-manganese grade, and R350HT, a heat-treated grade. R260 is suitable for lines with moderate traffic, while R350HT is used in high-wear areas and on heavy-haul or high-speed lines to provide superior durability and a longer service life.

Does EN 13674-2 cover all components of a railway turnout?

No, EN 13674-2 specifically covers the technical requirements for the switch and crossing rails themselves—the core profile-rolled steel products. It does not cover the design of the entire turnout system, nor does it cover other components such as bearers/sleepers, baseplates, fastening systems, or point machines, which are specified in other separate European Standards (ENs).

EU Strengthens Rail Safety: EN 13674-2 For Turnouts

Unpack EN 13674-2: the critical standard setting strict technical requirements for railway switch and crossing rails, ensuring turnout safety and reliability.

December 15, 2024 2:02 am

Understanding EN 13674-2: A Technical Guide to Switch and Crossing Rails

EN 13674-2 is a crucial European Standard that defines the technical delivery conditions for switch and crossing rails used in conjunction with Vignole (flat-bottomed) railway rails of 46 kg/m and above. This standard is a fundamental pillar for ensuring the safety, reliability, and interoperability of railway turnouts, which are among the most complex and high-stress components of the track infrastructure.

While EN 13674-1 covers standard plain line rails, Part 2 addresses the unique and more demanding requirements of rails used in switches, crossings, and turnouts. These components are subjected to significant dynamic loads, lateral forces, and concentrated stresses as trains are guided from one track to another, necessitating stricter manufacturing tolerances, specific steel grades, and rigorous testing protocols.

Scope and Core Requirements of EN 13674-2

The standard meticulously outlines the entire lifecycle of a switch rail, from material composition to final inspection. Its primary objective is to guarantee that these specialized rails can withstand the severe operating conditions they face, ensuring a long service life and minimizing the risk of failure.

Steel Grades: Specifies a range of non-heat-treated and heat-treated steel grades designed for varying levels of traffic density, axle loads, and wear resistance.
Chemical Composition: Defines the precise limits for elements like Carbon, Manganese, Silicon, and others to achieve the desired mechanical properties, weldability, and hardness.
Mechanical Properties: Sets minimum requirements for tensile strength, elongation, and hardness to ensure the rail can resist deformation and wear.
Geometric Tolerances: Imposes very strict tolerances on the rail’s profile, straightness, and surface quality, which are critical for smooth vehicle transition and minimizing wheel/rail impact.
Testing and Inspection: Mandates a comprehensive regime of testing, including ultrasonic internal inspection to detect hidden flaws, surface quality checks, and verification of all dimensional and mechanical properties.

Key Technical Specifications: Steel Grades and Mechanical Properties

The performance of a switch and crossing rail is directly linked to its material properties. EN 13674-2 specifies several steel grades, with the “HT” designation indicating that the rail has undergone a heat treatment process to significantly increase its hardness and wear resistance, making it suitable for high-stress locations.

Property	R260	R350HT	Description and Significance
Steel Grade Type	Non-heat-treated	Heat-treated (High Performance)	Heat treatment hardens the rail head, drastically improving resistance to wear and rolling contact fatigue.
Tensile Strength (min. MPa)	880	1175	Indicates the maximum stress the material can withstand before breaking. Higher strength is vital for rails under heavy axle loads.
Brinell Hardness (HBW)	260 – 300	350 – 390	A direct measure of resistance to indentation and wear. The higher hardness of R350HT is essential for the high-impact zones of a turnout.
Elongation at Fracture (A%)	min. 10%	min. 9%	Represents the material’s ductility. It ensures the rail can undergo some plastic deformation before fracturing, which is a critical safety feature.

The Critical Role in Turnout Integrity and Safety

Turnouts are points of discontinuity in the track, creating inherent geometric and structural challenges. The switch rails (or blades) are machined to a fine point to facilitate the guidance of the wheelset, while the crossing (or frog) is where the wheel has to bridge a gap in the rail.

Impact Load Management: The precise profiles and high-strength steel grades specified in EN 13674-2 are designed to manage the high impact loads generated as wheels traverse the switch and crossing, preventing premature material fatigue and failure.
Wear Resistance: The constant sliding and rolling contact in a turnout, especially at the switch blades and crossing nose, leads to accelerated wear. The hardness requirements of grades like R350HT directly combat this, extending the component’s service life.
Geometric Precision: Any deviation from the specified dimensional tolerances can lead to poor wheel-rail interaction, causing excessive noise, vibration, and even derailment risk. The standard’s strict geometric controls are therefore a primary safety requirement.

Relationship with EN 13674-1

EN 13674-2 is a direct companion to EN 13674-1, which covers plain line rails. While both standards share a common foundation in terms of steel manufacturing principles, Part 2 introduces more stringent requirements tailored to the specific functions of turnout components. The switch and crossing rails must be perfectly compatible with the adjoining plain line rails to ensure a seamless and safe track geometry, making the two standards interdependent for building a complete and compliant railway network.