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.