UIC Leaflet 527-2: Passenger Coaches – Dimensions of the Vehicle Ends

What is UIC Leaflet 527-2?

UIC Leaflet 527-2 is a fundamental technical standard titled “Coaches – Dimensions of the vehicle ends.” It provides the “blueprint” for the ends of Passenger Coaches to ensure they can be coupled together safely across all international networks.

The primary objective of this leaflet is to manage the physical interface between vehicles. It defines the exact positioning of Buffers and Draw Gear, as well as the Clearance required for gangways, brake pipes, and electrical jumpers. This standardization is the backbone of Interoperability in European passenger rail.

Geometric Requirements and Clearance

When a train moves through a sharp curve, the ends of the coaches shift relative to each other. UIC 527-2 defines the “Berne Rectangle” (also known as the Shunter’s Space), a safety zone that must remain clear of obstructions to protect staff when they are coupling or uncoupling vehicles.

• Buffer Positioning: Specifies the center-to-center distance of the buffers (1,750 mm) and their height above the rail level (940 mm to 1,065 mm).
• Draw Hook Projection: Defines how far the draw hook can protrude from the Underframe to ensure the Screw Coupler can reach the adjacent vehicle without excessive slack.
• Swing-out Limits: Mathematical limits on how much the vehicle end can “overhang” or swing out in a curve, preventing contact between the car bodies of adjacent coaches.

Protection of Connections

Passenger coaches carry various services (air, electricity, data) that must bridge the gap between vehicles. UIC 527-2 mandates the location of these interfaces:

• Brake Pipes: Standardized locations for the main brake pipe and the main reservoir pipe couplings.
• Electrical Jumpers: Positioning for the high-voltage heating cable and the low-voltage 18-core or TCN data cables.
• Gangways: Dimensions for the flexible bellows (UIC 561 style) that allow passengers to walk between coaches safely.

Structural Integrity and Safety

The vehicle end must be robust enough to handle the Longitudinal Compressive Forces transferred through the buffers. UIC 527-2 interacts with crashworthiness standards to ensure that the area around the buffers is reinforced, preventing the Underframe from buckling during minor shunting impacts.

Comparison: Freight vs. Passenger Vehicle Ends (UIC 527-2 context)