Overview
ISO 24675-2:2026 is an international standard developed by ISO for the railway sector, specifically addressing running time calculation for railway timetabling. This part of the ISO 24675 standard series outlines a practical procedure to create and verify distance-speed diagrams and speed curves by utilizing parameters defined in ISO 24675-1. The main objective is to determine the shortest running time for timetabling purposes by numerically integrating the speed curves. It is important to note that this document focuses exclusively on running time calculations intended for timetabling, excluding other applications.
Key Topics
- Distance-Speed Diagrams: Graphs that illustrate the relationship between a train’s speed and its position along the track. These diagrams are foundational in understanding the dynamic behavior of trains and are integral to accurate timetable planning.
- Speed Curves: Mathematical functions representing train speed changes as a function of position. Calculating the speed curve involves integrating railway-specific parameters governed by Newton's laws, such as tractive force, running resistance, gradient resistance, static mass, and inertia ratio.
- Running Time Calculation: The process features two main steps-generation of a speed curve using operational and infrastructure inputs, followed by integration of this curve to derive the shortest running time between two points (such as stations or passing places).
- Verification Procedures: The standard provides criteria and sample parameter sets to ensure accuracy. This includes validating calculated running times and speed curves against prescribed ranges and transition points.
Applications
ISO 24675-2:2026 brings practical value to a range of railway operations and stakeholders:
- Timetable Creation: Enables railway operators and planners to calculate the shortest possible running time, supporting reliable and efficient timetable development for daily, seasonal, and long-term rail operations.
- Operational Planning: Assists infrastructure managers in optimizing track usage, train scheduling, and crew deployment by providing accurate, verifiable running times.
- Punctuality and Efficiency: Contributes directly to the improvement of railway punctuality, helping railways remain competitive compared to other modes of transport and enhancing customer satisfaction.
- Quality Assurance: Promotes standardized verification of results, ensuring uniformity in running time computations across different organizations, networks, and countries.
- Interdisciplinary Integration: The standard serves as a reference for integrating rolling stock characteristics, infrastructure constraints, and operational rules in a consistent and transparent manner.
Related Standards
ISO 24675-2:2026 is part of a suite of standards dedicated to railway running time calculation and timetabling:
- ISO 24675-1:2022 – Railway applications - Running time calculation for timetabling - Part 1: Requirements: Specifies mandatory input parameters and their verification for running time calculation.
- ISO 24478:2023 – Railway applications - Braking - General vocabulary: Provides standardized terminology related to railway braking systems.
- IEC 60050-811:2017 – International Electrotechnical Vocabulary – Part 811: Electric traction: Offers vocabulary and definitions relevant to electric traction and railway applications.
By complying with these international railway standards, organizations benefit from harmonized methodologies for running time determination, contributing to safer, more predictable, and efficient railway services worldwide.
Keywords: railway running time calculation, speed curve, distance-speed diagram, railway timetabling, ISO 24675-2, train performance analysis, railway standards, timetable planning, operational railway efficiency, infrastructure planning.