ISO/TR 22131:2023 PDF

Overview

ISO/TR 22131:2023 - "Railway applications - Railway braking - Country specific applications for ISO 20138-1" is a Technical Report that supplements ISO 20138-1 by documenting national calculation approaches and examples for train braking. It explains country‑specific implementations (notably France, Japan and China), clarifies how to apply the general algorithms of ISO 20138-1, and presents the state of knowledge for calculating stopping and slowing distances, equivalent response time, brake performance and brake ratio.

Key topics and requirements

• Supplementary calculation methods: Presents alternative or adjusted calculation approaches that follow the same principles as ISO 20138-1 but differ slightly in formulation and assumptions.
• Country‑specific models:
  • France: a linear development model for trains operating in distributor “G” position (used by infrastructure managers) including an alternative equivalent response time definition and comparison with the ISO step model.
  • Japan: procedures for calculating brake ratio for individual vehicles, examples, and methods to derive equivalent response time from speed or brake cylinder pressure response.
  • China: stopping/slowing calculations for particular rolling stock including detailed treatment of train resistance, braking force, friction coefficients, dynamic mass and adhesion.
• Practical worked example: Test data and model comparisons (example: 1 000 m train in “G” position with derived equivalent response time 15.5 s and equivalent deceleration 0.89 m/s²) illustrating model accuracy versus measured stopping distances.
• Normative reference: ISO 20138-1:2018 is the primary reference; terms and definitions from that standard apply.

Practical applications

• Evaluating conformance of rolling stock and train braking performance with signalling and train control systems.
• Calculating signalling section lengths and safe braking distances for infrastructure design and operational rules.
• Assessing vehicle/consist brake behaviour for certification, safety cases or performance tuning.
• Adapting general ISO braking algorithms to national practices used by railways, manufacturers and test labs.

Who would use this standard

• Railway infrastructure managers and signalling engineers
• Rolling stock designers and brake system manufacturers
• Train performance analysts and test laboratories
• Safety assessors and regulatory bodies applying national calculation rules

Related standards

• ISO 20138-1:2018 - Calculation of braking performance (primary algorithm reference)
• EN 15355 (referenced for distributor “G” position definitions)
• ISO/TC 269 technical guidance on railway applications

ISO/TR 22131:2023 is particularly useful when implementing ISO 20138‑1 in national contexts or when comparing international calculation approaches for braking performance, stopping distances and brake ratios.