EN 15273-3: Defining the Railway Structure Gauge

What is EN 15273-3?

EN 15273-3 is the third part of the European Standard series titled “Railway applications – Gauges – Part 3: Structure gauges.” While Part 2 focus on the vehicles themselves, Part 3 is the primary manual for Infrastructure Management. It defines the “empty space” that must be maintained around the tracks to allow trains to pass without hitting platforms, tunnels, or signals.

The standard provides the mathematical formulas to calculate the Clearance Gauge, ensuring that even when a train is swaying due to wind or leaning into a curve, there is always a safety margin between the vehicle and fixed obstacles.

Calculations and Geometric Parameters

EN 15273-3 utilizes a sophisticated calculation method to determine the required space. It isn’t just a static box; it is a dynamic Swept Envelope that accounts for several variables:

• Kinematic Reference Profile: The base dimensions of the rolling stock permitted on the line.
• Dynamic Movements: Calculations for the lateral and vertical oscillations caused by the vehicle’s suspension.
• Curve Effects: Allowances for the “overthrow” of the vehicle (the way the middle of a car body swings inward and the ends swing outward on a curve).
• Track Tolerances: Margins for potential shifts in track position over time due to wear or ballast movement.

Safety and Electrical Clearances

A unique requirement of EN 15273-3 is the inclusion of electrical safety margins. For electrified lines, the structure gauge must not only prevent physical contact but also prevent electrical arcing:

• Electrical Clearance: A mandatory air gap between the energized overhead contact line (or pantograph) and grounded structures like tunnel ceilings.
• Passenger Safety: Ensuring that passengers leaning out of windows (in legacy stock) or standing on platforms are at a safe distance from the moving train.

Impact on Interoperability

Standardization under EN 15273-3 is vital for Interoperability across Europe. It aligns with the TSI INF (Technical Specifications for Interoperability – Infrastructure), meaning that a bridge built in Italy following these rules will safely accommodate a standardized freight wagon from Sweden.

Comparison: Structure Gauge Categories