UIC Leaflet 615-0: Design and Testing of Bogie Frames

What is UIC Leaflet 615-0?

UIC Leaflet 615-0 is a fundamental technical standard titled “Tractive units – Bogies and running gear – General provisions for the design and testing of bogie frames.” The bogie frame is the “backbone” of the Rolling Stock, responsible for supporting the vehicle body, transmitting traction and braking forces, and guiding the wheels along the track.

Given that the bogie is subjected to millions of cyclic loads over its 30-year lifespan, UIC 615-0 establishes the methodology to ensure its Fatigue Strength. It provides the criteria for both the design calculations and the physical validation tests required before a bogie can enter service.

Design Load Cases

The leaflet specifies several mandatory load cases that the Bogie frame must withstand. These represent the worst-case scenarios encountered during operation:

• Static Vertical Loads: The weight of the vehicle body and passengers, including allowances for dynamic “bounce.”
• Transverse (Lateral) Loads: Forces generated by centrifugal acceleration in curves and track irregularities.
• Twist Loads: Stresses caused by the track not being perfectly flat (e.g., transitions or poor track quality).
• Braking and Traction Forces: Longitudinal loads transmitted from the motors or brake calipers to the frame.

Testing and Validation Procedures

A core requirement of UIC 615-0 is the physical testing of a prototype frame. This process is divided into two main stages:

• Static Tests: The frame is subjected to loads exceeding the maximum operational forces to ensure there is no permanent deformation (Yielding).
• Dynamic (Fatigue) Tests: The frame undergoes millions of cycles of load combinations in a laboratory rig to simulate its entire service life. This ensures that no fatigue cracks develop in the welds or parent metal.
• Acceptance Criteria: Use of strain gauges to monitor stress levels at critical junctions (e.g., where the cross-beam meets the side-frame).

Transition to EN 13749

In the European regulatory environment, much of the technical content of UIC 615-0 has been superseded or absorbed by EN 13749. However, UIC 615-0 remains a vital reference for many non-EU networks and provides specific insights into the historical development of Structural Integrity standards for locomotives and power cars.

Comparison: Static vs. Dynamic Testing Requirements