Digital Twins Transforming Railway Infrastructure for the Future ERTMS Level 4

Introduction

The mobility field is recognized for its rapid and competitive research and development. Within this field, the railway sector stands out as one of the most crucial systems, experiencing continuous advancements with new technologies released every couple of years.

One of the primary challenges in the railway industry is to minimize the headway between trains. Reducing this interval is essential for increasing transportation capacity, enabling us to manage millions of passengers daily and meet high freight demand.

Recently, a technology referred to as "Digital Twin" has transitioned from theoretical discussions to practical applications. Many manufacturers are striving to adopt this technology to enhance their profitability and sustainability. Digital twins allow us to replicate physical systems virtually, enabling the prediction of operational issues before they occur.

Virtual twins facilitate the resolution of existing problems in physical systems, as they can provide insights that may not be visible to the human eye. Investigating issues often takes considerable time, but digital twins continuously monitor the physical systems and can provide immediate solutions.

What is Digital Twins?

A digital twin is a virtual replica of a physical system created in the digital realm. It simulates the product exactly as the real product does, including all its components.

You have the option to create a digital twin for either a single part of the product or the entire product, which can be referred to as a product digital twin. To develop this model, you begin by incorporating the necessary manufacturing data, ensuring that the virtual model possesses the same properties as the physical product.

Next, you will feed the virtual product with external factors that the real product encounters in the operational environment. Continuous monitoring of the physical system allows you to synchronize data between the real world and the virtual world, enhancing the accuracy and effectiveness of the digital twin.

What is ERTMS level 4 ?

ERTMS stands for the European Rail Traffic Management System. It is a standardized railway system designed to ensure all safety considerations in railway operations.

ERTMS Level 4 can be achieved by integrating ERTMS Level 3 with a concept known as virtual coupling. This system allows multiple trains to follow a lead train with considerably reduced spacing between them. Such close grouping enhances overall capacity and operational efficiency on the railway network while maintaining safety standards.

In ERTMS Level 4, we can visualize a scenario where multiple trains follow a lead train with very small headways between them. This close spacing enhances efficiency and capacity within the rail network. In contrast, ERTMS Level 3 operates with each train functioning independently. Here, every train communicates with its neighbouring trains to determine whether it can proceed or not, thus maintaining safe distances and ensuring operational integrity.

What is the added value of integrating between the digital twin and ERTMS level 4?

Implementing ERTMS Level 4 is a recent concept that remains largely in the research phase, representing an open challenge within the railway domain. Currently, several solutions are being developed at different levels, and the anticipated benefits of adding Virtual Coupling on top of ERTMS Level 3 are crucial for the future implementation of the standard. [1]

Virtual Coupling significantly relies on wireless communication, and the actual headways achieved through Virtual Coupling will depend on the precision of the train positioning systems. Factors such as odometer accuracy and satellite positioning resolution in future generations of ERTMS will play a vital role. [1]

Achieving very small headways necessitates a high-speed network with minimal latency, presenting a substantial challenge to ensure that the system operates as designed. [1]

This is where the value of the digital twin comes into play. By developing a testing environment through digital twin technology, we can simulate all parameters and safety cases within an environment that closely resembles real-world conditions. This approach eliminates the need for physical mock-ups, allowing us to assess the feasibility of implementations virtually and efficiently. [1]

The future

The challenges associated with the safe coordination of coupled train convoys open several future directions as prerequisites for real implementation of ERTMS Level 4. To this end, further research efforts are imperative to assess the implications of Virtual Coupling in various ERTMS operational scenarios. [1]

In particular, it is essential to investigate the safety-related impacts, considering new potential hazards that may arise from this advanced operational strategy. Additionally, performance evaluations need to be expanded to analyse capacity increases in common traffic scenarios, including those involving mixed traffic. [1]

To support this, It's planned for another scenarios to be studied, and these scenarios account for variations in topology and complex manoeuvres. Furthermore, we will address solutions for fast and reliable Train-to-Train communication, which is crucial for the successful implementation of Virtual Coupling and the overall efficacy of coupled train operations. [1]

resources:

[1] ERTMS/ETCS Virtual Coupling: Proof of Concept and Numerical Analysis Carlo Di Meo, Marco Di Vaio , Francesco Flammini , Senior Member, IEEE, Roberto Nardone ,Stefania Santini, Member, IEEE, and Valeria Vittorini

[2] Towards Railway Virtual Coupling Francesco Flammini Dept. of Computer Science and Media Technology Linnaeus University, Stefano Marrone Dept. of Mathematics and Physics University of Campania “Luigi Vanvitelli”, Roberto Nardone, Alberto Petrillo, Stefania Santini, Valeria Vittorini Dept. of Electrical Engineering and Information Technology University of Naples Federico II

[3] https://www.rail-kn.com/2021/11/ertms-level-4.html - 23-12-2024

[4] https://www.belcan.com/2023/01/16/pros-and-cons-of-digital-twin-technology/ -23-12-2024

[5] https://www.eraneos.com/impact-stories/reducing-train-delays-at-a-railway-company-with-a-digital-twin-simulation/ - 23-12-2024