When does UIC 805-01 apply?

It applies automatically to all railway rolling stock drawings unless specific tolerances are explicitly written on the drawing.

Why are tolerances for welding different than for machining?

Welding involves intense heat which causes the metal to expand and contract. UIC 805-01 provides larger 'Medium' or 'Coarse' tolerances for welded assemblies to account for this physical reality.

Does this leaflet replace ISO 2768?

While similar to ISO 2768 (General Tolerances), UIC 805-01 is specifically optimized for the larger dimensions and unique assembly methods found in heavy railway engineering.

UIC Leaflet 805-01: General Tolerances for Rolling Stock Construction

UIC Leaflet 805-01 establishes the general tolerances for the construction of railway rolling stock components. It provides the standardized permissible deviations for linear and angular dimensions, ensuring that parts manufactured by different suppliers fit together during assembly and maintenance.

September 25, 2023 9:09 am

What is UIC Leaflet 805-01?

UIC Leaflet 805-01 is a fundamental manufacturing standard titled “General tolerances for the construction of rolling stock.” In the complex assembly of a locomotive or wagon, thousands of components must fit together precisely. This leaflet defines the “default” tolerances that apply when specific tolerances are not indicated on a technical drawing.

Standardizing these Tolerances is vital for Interoperability and Rolling Stock maintenance. It ensures that a spare part manufactured in one facility will fit perfectly into a vehicle frame produced elsewhere, maintaining the Structural Integrity of the final assembly.

Scope of Application

The leaflet covers a wide range of fabrication methods common in the rail industry, providing a baseline for quality control during the Fabrication process:

Linear Dimensions: Permissible deviations for lengths, widths, and diameters of raw and machined parts.
Angular Dimensions: Limits for the accuracy of bends and the perpendicularity of structural members.
Welded Structures: Specific tolerances for Welding assemblies, accounting for the natural thermal distortion that occurs when welding heavy steel plates.
Form and Position: General limits for straightness, flatness, and parallelism, ensuring that long components like the Underframe remain true.

Tolerance Classes

UIC 805-01 typically categorizes tolerances into different “classes” (e.g., Fine, Medium, Coarse). The designer selects the class based on the function of the part:

Safety-Critical Interfaces: Usually require finer tolerances to ensure correct load distribution and prevent vibration-induced wear.
Non-Structural Components: May use coarser tolerances to reduce manufacturing costs without affecting safety.

Technical Delivery Conditions and Quality

Adhering to these Technical Delivery Conditions simplifies the procurement process for railway undertakings. It allows for:

Interchangeability: Guarantees that components like buffer beams or door frames can be replaced without extensive on-site modifications.
Streamlined Inspections: Quality inspectors use the leaflet’s tables to quickly determine if a fabricated component is within acceptable limits.