PSI Blog

Autonomous Rail Transport: How to Benefit From Modular Control Systems?

28 Oct 2021 - Transport, Technology, Artificial Intelligence

Passengers benefit from higher train frequency, as well as better timetable stability and punctuality through automated driving. Source: PSI Transcom
Passengers benefit from higher train frequency, as well as better timetable stability and punctuality through automated driving. Source: PSI Transcom

Autonomous rail transport is already reality in major European cities. It is gaining momentum as an important piece in the puzzle of modern mobility concepts. It turns out that modular, agile control systems are best suited as a central dispatching system.

Why are more and more transportation companies opting for Automatic Train Operation (ATO)? The reason is obvious: Because the mobility of the future must be sustainable, demand-driven and reliable. Autonomous driving plays a key role here. It means that all processes operate automatically or semi-automatically depending on the degree of automation:

  • Driving and stopping,
  • opening and closing the doors, or
  • stopping immediately in the event of a fault.

Use Case: S-Bahn Hamburg Goes Digital

S-Bahn Hamburg is currently taking the next step toward sustainable public transportation through the “Digital S-Bahn Hamburg” pilot project. In the future, four regional trains will be running in a highly automated manner between the city’s Berliner Tor and Bergedorf/ Aumühle stations. The drivers of these trains will only intervene in the event of irregularities or faults. If the project is successful, the entire regional train network will be incrementally digitized.

S-Bahn Hamburg is doing this using its PSItraffic Train Management System. This solution has been monitoring and controlling Hamburg’s regional rail traffic and reliably providing passengers with train connection updates for over 20 years now. As part of the ATO equipment, the system transmits the timetable and train stop information to the ATO system.

In the future, this information will be transmitted via radio to the on-board ATO system in the form of journey and segment profiles – including the stopping locations – depending on the tensile strength available. This information thereby forms the foundation for highly and fully automated train operation.

Resource-Saving and Climate-Friendly on the Rail

A key impetus behind this development is the environmental aspect. Smoother acceleration, driving and braking make these trains significantly more resource-efficient and thus more climate-friendly in transit. ATO in the city can also provide the answer to the growing demand for capacity and availability.

ATO allows train frequencies to be increased in line with demand while maintaining a high level of safety and requiring only minor structural changes to the lines.

Some major European cities already have autonomous metro trains running at intervals of just 90 seconds based on Communication-Based Train Control (CBTC) systems. Passengers there benefit from 

  • the higher train frequency,
  • the improved schedule stability and
  • punctuality.
PSItraffic connects the essential systems in railway operations in various modular expansion stages. Source: PSI Transcom
PSItraffic connects the essential systems in railway operations in various modular expansion stages. Source: PSI Transcom

ATO in Urban Traffic

An ATO system essentially consists of the control system and the ATO components, which can be trackside as well as on-board. While the former are responsible for trackside communication, the latter collect static and dynamic route and schedule data from the Traffic Management System and transmit it to the ATO on-board devices.
These onboard components calculate the optimal driving profile and control the accelerators and brakes.

Thanks to automated control and safety systems, rail traffic already operates with a high degree of automation today, which provides a basis for further development towards ATO. This is partly due to the stable environment. However, this is precisely the point where significant differences can be identified within rail transport.

Light rail systems, for example, are based on a completely closed network of lines and are exposed to significantly fewer external risks due to the tunnel system.

No level crossings or interfaces with other lines exist, and storm damage does not occur. Safety on the platform can also be reliably ensured by automatically retractable walls, as has already been demonstrated in practice.

Higher speeds, dependencies on other rail lines and stronger external influencing factors such as the weather have to be taken into account in long-distance traffic. Another challenge is the lack of standards and numerous proprietary interfaces. There is also a lack of uniform system boundaries as a result.

PSItraffic Train Management System is the basis for centrally monitoring and controlling train operations. Source: PSI Transcom

Adaptable to Requirements

So are generalist control systems equally well suited as a central data hub to long-distance and freight traffic as well as to less complex, autonomous urban traffic? Especially in an urban context, more agile systems that can be adapted as needed prove their worth, as the example of the S-Bahn Hamburg shows. They allow loose system boundaries to be individually adapted.

Therefore, software solutions such as PSItraffic, which are fully integrated into different system landscapes via open, standardized interfaces, are also suitable in an ATO system as a central dispatch interface to control rail operations. In particular, communication between the control system and the vehicle-side ATO onboard unit (OBU) via standardized interfaces such as subset 131 and 126 enables optimum flexibility in the selection of the vehicle supplier or the retrofitted OBUs.

The Modular Design Is Crucial

Highly automated control and safety systems offer a good basis for the further development towards ATO. Source: PSI Transcom
Highly automated control and safety systems
offer a good basis for the further development
towards ATO. Source: PSI Transcom

It means that the system can be expanded in different ways to combine the essential systems in rail operations – from short-term schedule dispatch, precise workshop management and optimized route and personnel scheduling through train control and passenger information.

The advantage compared to simple train scheduling: The system considers the entire route network and takes on the dispatch management. Faults or conflicts can thus be identified early, and dispatchers receive optimized suggestions for how to deal with issues in real time. Dispatch decisions are communicated to other systems at the push of a button. In conjunction with ATO operation, highly repetitive work is eliminated and the optimal capacity utilization of available resources is enabled.

In short: Interlocking technology, which has grown over the decades and is often heterogeneous, requires a future-oriented and flexible control system with variable interfaces for connection to a central control center solution.

In contrast, ATO or CBTC solutions, as a basic evolution of a train control system, are not very suitable for the fully automatic control of entire networks via schedule dispatch and including the integration of neighboring systems. In addition, a generalist system requires larger investments in infrastructure and interlocking technology.

Agile Control Systems Also Leading in ATO Operations

Just like industry, rail transport will have to be measured even more in future using key figures for resource conservation and climate neutrality. In order to simultaneously meet growing needs and find answers to the ongoing problem of new recruits, autonomous rail transport is indispensable, especially in an urban context.

Technically, the transport systems already have a reliable basis. This also applies to agile and open control software, which also plays the leading role in the interaction with the other ATO components.

Read more about PSItraffic Train Management in our current brochure.


What is your opinion on this topic?

Robert Baumeister

Division Manager Train Management, PSI Transcom GmbH