Automatic Train Operation is the latest addition to a growing portfolio of train control systems which Stadler has built up over the past decade, as the group’s Head of Signalling Marc Trippel explains to Toma Bačić.
‘We are very proud to be implementing this forward-looking project’, he says. ‘For Stadler Signalling, it represents an important milestone in the development of modern, digital train control systems, and at the same time a significant step for automated rail transport in Switzerland.’
A first step with AngelStar
Wallisellen-based Stadler Signalling was founded in 2017, with the primary goal of providing ETCS in-house through the AngelStar joint venture with MerMec.
‘The primary objective at the time was to have an alternative to the established suppliers’, Trippel explains. ‘Back then, we had to acquire critical subsystems from our direct competitors, which could lead to some interesting situations. The development of Guardia was basically leveraging MerMec’s existing competences, while the AngelStar joint venture combined MerMec’s technology with Stadler’s market access. It has been a successful example of combining technology and market to create value. By the end of 2025 we had 11 generic country authorisations for Guardia across Europe.’
The first Guardia implementation was on Stadler Flirt multiple-units for Koleje Mazowieckie; they were approved for regular service in June 2020 using ETCS Levels 1 and 2 to Baseline 3.4.0 with dynamic transitions to and from Poland’s national train protection system SHP. Guardia was also installed on BLS Flirts ordered in January 2018. These were rolled out from mid‑2019 and entered service from 2021.
‘The joint venture is still functioning’, Trippel confirms. ‘If somebody wants to compare the speed of development and the results to the other ATP suppliers, I would say that the joint venture has been highly successful. The main challenge has been to try and keep up with the TSI changes; now the big topics are Baseline 4 and how to prepare for the migration from GSM-R to FRMCS.’
Portfolio expands
Stadler Group acquired Swiss firm BÄR Bahnsicherung in 2021 and the German signalling company BBR Verkehrstechnik in December 2022, with its headquarters in Braunschweig. Adding 270 employees to the business, BBR brought to the portfolio electronic interlockings, train detection systems, point control equipment and onboard signalling components. A dedicated signalling division was established in January 2022, and BBR was renamed Stadler Signalling Deutschland.
Today, Stadler Signalling offers a range of tailored systems for main line railways, regional lines, light rail and metro. As well as ATO and ETCS, its portfolio includes various national train control systems and CBTC. Trippel says the business is expanding its operations ‘in very different directions’, from automation through classic signalling to passenger information systems.
From CBTC to ATO
Trippel reports that Stadler Signalling is actively involved with several automation projects, of which the Waldenburgerbahn is probably the most advanced.
‘Working with two small operators in Switzerland, we started developing our CBTC solution from scratch’, he explains. ‘We were investigating what might be possible, and we focused on the software where we deployed the most modern architecture. Our target is GoA4, so the technologies have been developed for that level of automation. What is important is that authorities and the regulations play an extremely important part in the process.’
Developed at Wallisellen, Stadler’s Nova Pro CBTC replaces traditional fixed-block signalling with moving block. The system calculates a dynamic safe distance between trains, based on their position, speed, braking capability and track conditions. This allows trains to run at shorter headways, increasing line capacity whilst increasing safety. Nova Pro uses continuous wireless communication between track and train.
Innovation in Waldenburg
Originally built to 750 mm gauge, the 13 km regional railway linking Liestal and Waldenburg southeast of Basel has been operated by Baselland Transport since 2016. It was closed in April 2021 for complete reconstruction as a metre-gauge light rail line, reopening in December 2022. As well as a fleet of 10 Tramlink LRVs, Stadler supplied its Nova Pro CBTC supporting attended ATO to GoA2. BLT received a licence for automated operation at GoA2 from the Bundesamt für Verkehr in December 2025.
Once the doors have been closed and the driver has authorised departure from each stop, the journey runs fully automatically, helping to improve performance. The CBTC controls the speed, ensuring compliance with the speed limits, optimises the control of level crossings and stops the train precisely at the next station. The driver supervises the operation, and is on hand to intervene if necessary. However, Trippel says that BLT is now planning to implement fully unattended vehicle manoeuvring to GoA4 in its new depot at Waldenburg from the end of 2026. Successful preliminary tests have already been carried out, he adds.
‘For Waldenburgerbahn, GoA4 means that a vehicle wakes up in the depot, shunts as necessary, and then goes autonomously to the first station. There, the driver will board the train, and 2 min later, also the passengers. From that moment, all operations will be GoA2 to the end of the service in the evening. The driver will disembark, and the train will go back to the depot fully autonomously at GoA4, including a visit to the washing plant. Trains will couple and decouple completely autonomously.’
In October 2025, Montreux–Vevey–Riviera Transport awarded Stadler a contract to equip the 10·4 km Montreux–Rochers-de-Naye rack railway with Nova Pro. That followed an earlier contract signed in May 2025 for the supply of eight trains to re-equip the 800 mm gauge line which climbs to the summit of Rochers-de-Naye at 1 973 m above sea level. The new panoramic trainsets are due to be introduced from 2029, replacing 40-year old stock.
Automation on the rack
Stadler is currently developing an ATO package for the 1 200 mm Rheineck – Walzenhausen line near St Gallen. This 2 km line has different infrastructure characteristics, posing challenges for the automation. Over the first 500 m, an adhesion-worked section parallels the Rorschach – St Margrethen main line, before crossing a main road by a level crossing protected with barriers. After passing the depot spur, the line joins the rack and climbs steeply to reach Walzenhausen.
In September 2022 operator Appenzeller Bahnen, ordered a new rack-and-adhesion railcar from Stadler, along with CBTC to enable fully automated operation at GoA4. AB staff in the operations centre would be able to intervene by remote control.
‘Reineck – Walzenhausen is a simple line’, says Trippel, ‘but it is the first project in Europe where the train will run at GoA4 on the open ground. Don’t get me wrong, but the technical solutions are not changing much. What is changing is the authorisation of the system, at all levels, from the operator to the authorities. What should be done if something happens? What we are doing at Stadler is adapting metro automation technology to an open ground line. We are more focused now; the real value-adds for us are the LRV automation, where we can offer more flexibility for the operators.
‘BAV has been very supportive, and there is great co-operation between Apenzeller Bahnen, BAV and Stadler regarding GoA4. The process is going surprisingly well.’ Formal operation is expected from 2028.
Other CBTC and ATO projects
In 2024, Stadler won its first CBTC contract in North America. Metropolitan Atlanta Rapid Transit Authority awarded Stadler Signalling a US$500m contract to install Nova Pro CBTC across its entire metro network, replacing the legacy signalling and enabling GoA2 operation. In July 2025, Stadler established the Signalling North America business unit, with offices in Atlanta, focused on its signalling and train control activities, commenting that this was the first major international expansion of the Stadler Signalling Division beyond Europe. ‘MARTA is slightly different from an ordinary metro’, comments Trippel, suggesting that some sections ‘can be considered as light rail’.
Meanwhile, Stadler is supplying trains for the Lisboa Metro that are equipped for GoA2, with the potential for future upgrading to GoA4 driverless operation. The Lisboa network is equipped with Trainguard MT CBTC from Siemens Mobility, with which the Stadler rolling stock will have to interface.
The two companies are also working together on a recently signed order to supply 226 four-car trainsets for the København S-bane, with options for up to 100 more. Siemens will be responsible for the automation, signalling and core train systems such as traction, while Stadler will be responsible for the mechanical parts, car bodies and train manufacturing.
Conventional signalling
Stadler Signalling is supplying a conventional system for the Bergen Bybanen light rail network rather than CBTC or ETCS. The contract signed in April 2025 is valued at ‘approximately €50m’. According to Stadler, the contract initially covers ‘a high-performance, future-proof’ signalling and train control system for the extension to Åsane, with additional phases to be agreed as options. This will be a SIL 2 system, with individual components meeting SIL 4.
The package includes train detection using track circuits or wheel sensors, train protection and train identification systems, signals and switch point heaters, as well as a fully equipped control centre with multiple workstations and training consoles. Almost all of this will be manufactured at the company’s Braunschweig facility.
Stadler is also supplying interlockings as part of the Sihltal Zürich Uetliberg Bahn’s SFr800m ‘SZU_4.0’ modernisation programme, under a SFr34m contract awarded in October 2024. Group Chairman Peter Spuhler said at the time that the SZU contract was ‘a milestone for Stadler’, as a breakthrough into the Swiss standard gauge market. Stadler is also supplying 17 Flirt S-Bahn trainsets valued at SFr160m, and these are expected to enter service by mid-2028.
In January 2025, Chemins de fer du Jura signed a contract for Stadler to renew its signalling at Tavannes station and Orange depot, as part of a project to modernise its Tavannes – Le Noirmont line by 2027. Valued at SFr4·3m, the deal envisages the use of the company’s Eurolocking electronic interlockings. CJ had previously commissioned Stadler to overhaul the safety systems at Tramelan, following work to upgrade the installations at Bellevue, Saignelégier, Alle, Alle Centre, Vendlincourt and Bonfol.
Stadler significantly expanded its signalling portfolio in March 2026, by signing a non-exclusive strategic co-operation accord with Ebblo (formerly Trapeze Group). The companies are planning to cooperate on digital passenger information for local public transport. Stadler is contributing its MOFIS passenger information monitor, which was developed by Stadler Signalling. This is specifically designed for outdoor use in all environmental conditions, including direct sunlight. The company says the advanced LCD screen based on TFT technology will be integrated into Ebblo’s Intermodal Transport Control System.
ETCS retrofitting
Trippel says there are ‘enormous business opportunities’ from retrofitting existing rolling stock with ETCS, another market in which Stadler Signalling is active. Manufacturer capacity is considered a major bottleneck in the retrofitting of approximately 13 000 locomotives and multiple units in Germany alone over the coming years. Retrofitting ETCS without the involvement of the vehicle manufacturer is expected to contribute significantly to a faster roll-out.
In November 2023, DB, Stadler and AngelStar successfully returned to service a DB Cargo Class 185.2 Traxx locomotive that had been fitted Guardia Baseline 3.4.0 onboard equipment without involving the manufacturer. Trippel notes that the prototype installation had to overcome a particularly complex legislative process to get the locomotive (re)approved. The retrofit began in October 2020 and was completed by July 2021, but ERA approval for the ‘First in Class’ application was only received in October 2023. The first series installation required a much simpler approval under the so-called Conformity to Type process.
The first Flirt trainsets fitted with Guardia ETCS for use in Belgium, the Netherlands and Germany began running in March 2024, as part of the three-country service operated by Arriva. The eight trains were retrofitted by Stadler in collaboration with the operator. However, the ETCS is currently only required on the Belgian section of the route, as the Dutch and German sections are still using the legacy Class B systems ATB and PZB respectively.
In January 2023 Stadler won a Europe-wide tender to retrofit Guardia on up to 80 infrastructure maintenance vehicles for DB Netz, starting with an initial eight maintenance and track service vehicles of classes 711.1 and 741.X. Guardia has also been fitted to the DB Advanced Train Lab of Class 605 that was exhibited at InnoTrans 2022.
‘Retrofitting is challenging because of the certification process’, Trippel explains. ‘The real problem is not fitting Guardia to the existing vehicle, but getting recertification of a 10 or 20 year old vehicle to the latest standards.’
Stadler increases profitability and sales
AI challenges ahead
Looking forward to the next developments in the signalling sector, Trippel suggests that ‘the huge question is how the rail industry will manage and deploy AI in safety. How do we leverage AI within the safety management system, and how do we use it in a safety- critical way? The question is not so much about the sensors and the hardware but about analysing the data.
‘The railway ecosystem is demanding, but the volumes are small. So we have to leverage solutions from other industries, and adjust them for railway applications. We need to focus on the adaptation. We don’t need to reinvent every time, but we do have to think carefully about what the railway needs.
‘We need to have open discussions with the authorities. While we are getting more into digital systems and software, the certification and authorisation processes are still very mechanically driven, according to legislation laid down 50 or 100 years ago. The authorities really need to adapt their processes. The solution is not just in the hands of the suppliers, but also the authorities. And we have seen that the certification culture grows over time.’
See also
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