Slovakia launches ETCS tender for ZSSK diesel locomotives

Slovak national passenger rail operator ZSSK has launched a public tender to equip a group of its diesel locomotives with the European Train Control System (ETCS), marking a new phase in the country’s rollout of modern train protection technology beyond the electrified core network.

Tender targets retrofit of core regional diesel fleet

According to publicly available procurement information, the new tender focuses on retrofitting selected ZSSK diesel locomotives with onboard ETCS equipment compatible with the latest European standards. The project is intended to cover locomotives used on key regional and interregional routes where conventional lines interface with ETCS-equipped main corridors.

Reports indicate that ZSSK aims to future proof its diesel fleet as more Slovak routes transition to ETCS operation. While many of the country’s modern electric units and locomotives already feature ETCS, large parts of the passenger diesel fleet still rely on legacy national train protection systems, which can limit cross-border operations and complicate traffic management on upgraded lines.

The tender is expected to include the design, supply, installation and testing of complete onboard ETCS packages, as well as integration with existing braking, signalling and communication systems on each locomotive. Industry coverage suggests that bidders will also be required to provide driver interfaces, diagnostics and lifecycle support to keep the equipment aligned with future software and baseline updates.

The contract scope is structured so that the winning supplier can work within ZSSK’s operating depots and heavy maintenance facilities, reducing downtime by scheduling installations alongside scheduled overhauls where possible. This approach is intended to keep regional services running while the fleet is progressively upgraded.

Part of wider ETCS and ERTMS deployment in Slovakia

The diesel locomotive tender comes as Slovakia accelerates its wider adoption of the European Rail Traffic Management System (ERTMS), of which ETCS is a core component. Public documents from European funding programmes show multiple ongoing initiatives to equip Slovak rolling stock and infrastructure for interoperable operation on key international axes.

Earlier funding decisions highlighted support for ETCS installations on electric multiple units and control cars in the ZSSK fleet, as well as separate projects to introduce ETCS on locomotives operated by freight carrier ZSSK CARGO. That work has been framed as essential for ensuring that both passenger and freight services can use upgraded corridors without technical restrictions.

Infrastructure manager Železnice Slovenskej republiky is also progressing with ETCS deployment on selected main lines, including routes that form part of the broader European core network connecting Slovakia with neighbouring countries. As more trackside sections are commissioned, demand grows for compatible onboard equipment across all traction types, including diesel locomotives that regularly venture beyond non electrified branches onto upgraded corridors.

By adding diesel locomotives to the portfolio of ETCS equipped vehicles, ZSSK positions itself to offer through services that do not require locomotive changes purely for signalling compatibility. This is particularly relevant on routes where diesel hauled trains start on non electrified territory and continue over electrified, ETCS supervised main lines for the final part of their journey.

Improved safety, capacity and cross-border interoperability

ETCS is designed to continuously supervise train speed and movement authority, helping to prevent collisions and signal passed at danger incidents. For ZSSK’s diesel fleet, which often serves curving regional routes and mixed traffic corridors, the introduction of ETCS is expected to bring a uniform level of safety comparable with that already available on modern electric traction.

Beyond safety, network planners highlight that widespread ETCS deployment can support higher line capacity. With trains being supervised in real time, infrastructure managers can optimise headways, allowing more services to operate on busy sections without compromising safety margins. Bringing diesel locomotives into the ETCS ecosystem ensures they can participate in these capacity gains rather than becoming operational bottlenecks.

Interoperability is another key consideration. Slovakia sits on important freight and passenger corridors between Central and Eastern Europe, and cross-border services increasingly rely on ETCS as the common standard. Diesel locomotives equipped with ETCS can potentially run further into neighbouring countries, provided they also meet any additional national requirements, reducing the need for locomotive changes at borders.

For passengers, the change will be largely invisible, but the underlying technology should contribute to more reliable timetables and fewer disruption events related to signalling constraints. For operators, harmonising signalling equipment across fleets can simplify training and operational procedures, especially as more lines migrate toward ETCS-only operation over the coming years.

Funding, timelines and industry interest

Publicly available European documents indicate that Slovakia has been drawing on EU level transport funding to co finance various ETCS initiatives, including rolling stock retrofits and infrastructure works. The new diesel locomotive tender is expected to align with these broader funding frameworks, allowing ZSSK to share investment costs between national resources and European programmes where eligibility conditions are met.

While detailed timelines for contract award and fleet conversion have not been formally summarised in a single public source, the structure of ongoing ETCS projects in Slovakia suggests that implementation would be phased. Initial locomotives are likely to be equipped and tested first, with lessons then applied to subsequent batches to streamline installation and certification.

Rolling stock and signalling suppliers active in Central Europe have already gained experience fitting ETCS equipment to similar diesel locomotive types, including conversions for freight and passenger operators in neighbouring countries. This background is expected to encourage interest from a range of bidders, all seeking to demonstrate compatibility with Slovak infrastructure and existing onboard systems.

Once the tender is awarded, ZSSK will be able to integrate the upgraded diesel locomotives into regular diagrams on lines where ETCS is already installed, gradually increasing the share of services that can benefit from the harmonised signalling environment.

Strategic step toward a unified digital railway

The decision to launch an ETCS tender for diesel locomotives underlines a strategic shift toward treating train protection as a fleet wide, rather than corridor specific, capability. As more European countries set long term targets for ERTMS deployment, operators are under pressure to ensure that all traction types, including older diesel classes, can interface reliably with modern signalling.

For Slovakia, extending ETCS beyond high speed or main electrified routes and into the diesel hauled segment of the network supports ambitions for a more integrated, digitally supervised railway. Regional communities served primarily by diesel traction stand to gain from the same safety and reliability standards that apply on flagship intercity routes.

The tender also reflects an awareness that diesel traction will remain necessary on many non electrified lines for years to come, even as broader decarbonisation efforts proceed. By equipping these locomotives with ETCS now, ZSSK and its partners aim to avoid creating a two tier system in which only certain trains can access upgraded infrastructure or participate fully in international traffic flows.

As procurement progresses and contract details emerge, the diesel ETCS programme is set to become a visible component of Slovakia’s wider shift toward interoperable, digital train control, complementing parallel investments in electrified rolling stock and infrastructure modernisation across the national network.