Zugführer in einem ATO-Führerstand


first train runs completed successfully in compliance with UNISIG standards

Date: 07.05.2020


In January 2020, Siemens Mobility achieved yet another milestone in the development and market rollout of automatic train operation (ATO) on an SBB line. We are proud to be the world’s first manufacturer to operate with an ATO onboard unit in accordance with the latest UNISIG standards.


Within the scope of a proof of concept commissioned by SBB as part of its smartrail 4.0 program, GoA2 commissioning runs are being carried out using ETCS L2 on the Swiss Lausanne - Villeneuve line. The goal of the second phase of the project is to demonstrate the functionality and interoperability of the interfaces to the ETCS onboard unit (SUBSET-130) and the vehicle control unit (SUBSET-139) in accordance with the latest UNISIG specifications, following on from the interface to the ATO trackside system (SUBSET-126) in the first phase.

SBB provided the required ATO trackside equipment, a proprietary development as part of the smartrail 4.0 innovation program.


After a preparatory phase in which the various components were developed, four test weekends followed between November 2019 and January 2020. Each Friday evening, the project team equipped the train with a mobile ATO box for the night-time test runs. On Monday morning, the train was available again for commercial operation, with the mobile ATO box having been removed.


Now that the joint tests have been successfully completed, SBB is conducting further test runs on its own as part of the smartrail 4.0 program

Operating principle


The driver activates the ATO with the push of a button at the train station or during the journey. The train then automatically moves to the next stop, even though the driver can take back control at any time. The train equipped with our ATO system adheres precisely to the current scheduling instructions from SBB’s Rail Control System (RCS) dispatching system.


Particularly worth mentioning is the successful interoperation of a Radio Block Center (RBC) from Thales, a dispatching system and an ATO trackside system (ATO-TS) from SBB, and our very own ATO onboard unit (ATO-OB) on a vehicle from Stadler Rail. We used a converter box to implement the interface between the ETCS onboard unit and ATO. This allows the currently installed version of ETCS to be used with ATO, instead of having to upgrade to a future version.


In addition to the correct and exact stopping at the defined stopping points, we have shown, for the first time, that automatic door control with ATO is very well possible. The ATO trackside specifies on which side of the train the doors are to be released at the next train station. Once the train stops, ATO opens the doors automatically. The doors then close again automatically as soon as the stopping time has expired. We also successfully tested temporary restrictions such as speed restrictions and a function that allows drivers, for example, to deliberately omit stops in the case of demand stops.


Guaranteed passenger comfort


Impressive features include automatic approach, acceleration, smooth braking, and precise driving along the monitored brake curves. All told, this ensures a very high level of passenger comfort. Particularly at the station entrances, we identified positive reserves compared with manual operation. With ATO, the train enters the station faster than a locomotive driver and still comes to a halt at the defined stopping point.


Following the four planned test weekends, the project has been successfully completed for us. The functionality of all tested interfaces was successfully demonstrated in accordance with the latest version of the UNISIG specifications. 


The successful completion of the test operation is primarily thanks to the excellent collaboration between all project participants.


The ATO-OB software was developed in Berlin (Germany), while the different Siemens Mobility departments in Wallisellen (Switzerland) were responsible for adapting the ETCS configuration, creating the software for the ATO gate and the ATO box, and preparing the documentation required for the operating license. As a result of the test project, Siemens Mobility now has a functioning ATO onboard unit in accordance with the SUBSETS 125, 126, 130 and 139. We are, therefore, perfectly equipped for further ATO projects to come.

ATO with UNISIG-Standard

Automatic Train Operation (ATO)

The interoperable ATO Unboard Unit from Siemens Mobility enables energy-efficient and rolling stock-friendly travel and shortens the train sequence, which has a positive effect on the timetable.

First ATO run worldwide with UNISIG standard


In combination with an RBC from Thales, a dispatching system and an ATO-TS from SBB as well as a locomotive from Stadler, the ATO-OB from Siemens Mobility proved its interoperable functionality and operational capability according to UNISIG standards for the first time worldwide at the beginning of 2020. The performance in terms of adherence to time schedules and stopping accuracy was extremely promising even without additional optimization measures (e.g. additional balises). 


Would you like to learn more about the functions, components and architecture of the ATO solution? Than download the data sheet!