Key Takeaways & Executive Findings
- •• • MB signalling reduced trailing train travel time by 70 s (2.5% of total time) relative to FB under an injected 5th-station departure delay, demonstrating tangible throughput gains for high-density corridors where headway recovery directly impacts schedule adherence and operational cost. • • The aggressive driver model in simulation B elicited a more significant signalling intervention, with MB producing a more jagged speed profile due to frequent activation; this underscores the trade-off between travel time reduction and energy consumption or passenger comfort, necessitating careful tuning of control laws. • • The modular tool integrates RBC, OBU, vehicle dynamics, and driver behaviour, enabling time-efficient simulation of diverse scenarios; this reduces reliance on costly on-site testing, potentially cutting commissioning timelines and costs for signalling upgrades by enabling virtual validation. • • Findings are explicitly limited to the two case studies (simulations A and B) on a 12-station line with two trains; generalisation requires parametric investigation across parameters such as headway, delay magnitude, and driver aggressiveness, highlighting the need for sensitivity analyses before deployment decisions.
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Abstract
This paper presents a time-based modular simulation tool implemented in MATLAB® and Simulink® for evaluating fixed block (FB) and moving block (MB) railway signalling systems. The simulator integrates the Radio Block Centre (RBC), On-Board Unit (OBU), vehicle longitudinal dynamics, and a driver behavioural model to replicate realistic train operations. Two case studies are conducted on a main railway line with twelve stations, involving a leading and a trailing train with identical mechanical characteristics. An unexpected departure delay of the leading train at the fifth station reduces the headway, forcing the signalling system to intervene. Simulation A employs identical driver parameters for both trains, while simulation B assigns an aggressive and less responsive driver to the trailing train, resulting in a more pronounced signalling action. Results indicate that MB signalling reduces the trailing train's travel time by 70 s (2.5% of total time) compared to FB, albeit with a more jagged speed profile due to frequent activations. The authors caution that these findings are limited to the two case studies and that a comprehensive parametric investigation is necessary for generalised conclusions. The tool aims to reduce on-site testing of railway signalling systems by providing a flexible platform for scenario analysis.
1. Introduction
Existing commercial signalling systems, particularly fixed block (FB) architectures, impose rigid separation distances that constrain capacity on increasingly congested rail networks. While moving block (MB) systems theoretically overcome these limitations by enabling absolute distance separation, their deployment has been hindered by the lack of validated simulation tools capable of replicating the complex interactions between ground control, on-board equipment, and human driver behaviour. This gap forces reliance on expensive and time-consuming on-site testing, delaying the adoption of MB technology.
This work addresses the bottleneck by developing a modular time-based simulation tool that integrates the Radio Block Centre, On-Board Unit, vehicle longitudinal dynamics, and a driver behavioural model. The tool is implemented in MATLAB® and Simulink® and is validated through two case studies on a realistic 12-station line with a leading and trailing train. By injecting a departure delay and varying driver aggressiveness, the authors demonstrate the tool's capability to capture signalling interventions and quantify performance differences between FB and MB, providing a foundation for reducing physical testing and accelerating signalling system assessment.
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M. Barbaro, I. La Paglia, L. Bernardini, G. Bucca, R. Corradi, M. Bocciolone, A. Collina (2026). A modular simulation tool for fixed block and moving block railway signalling systems. Railway Engineering Science (铁道工程科学). https://doi.org/10.1007/s40534-025-00401-8
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Frequently Asked Questions
What is the quantified travel time benefit of moving block over fixed block under the tested delay scenario?
In simulation B, moving block reduced the trailing train's total travel time by 70 seconds, equivalent to 2.5% of the total time, compared to fixed block. This improvement stems from MB's ability to maintain shorter safe distances, allowing faster recovery from the injected departure delay.
How does driver behaviour affect signalling system performance in the simulations?
Assigning an aggressive and less responsive driver to the trailing train (simulation B) caused the train to approach the leading vehicle more rapidly, triggering a more significant signalling intervention. This resulted in a more jagged speed profile under MB due to frequent accelerations and decelerations, highlighting the sensitivity of signalling performance to human factors.
What are the limitations of the presented results, and what further work is required?
The results are confined to two case studies (simulations A and B) on a 12-station line with two trains. The authors explicitly state that generalised conclusions require a comprehensive parametric investigation across variables such as headway, delay magnitude, and driver parameters, which is identified as a primary future target.
What are the key components integrated into the simulation tool?
The tool incorporates the Radio Block Centre for communication, the On-Board Unit for generating reference speed profiles, vehicle longitudinal dynamics, and a driver behavioural model. This modular architecture enables simulation of both fixed block and moving block signalling logics under various operational conditions.
What is the potential industrial impact of this simulation tool?
By providing a time-efficient platform for testing signalling systems, the tool can reduce reliance on on-site testing, which is costly and disruptive. This may accelerate the validation and deployment of advanced signalling systems like moving block, ultimately improving railway capacity and schedule reliability.
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