Prover Technology is a Swedish supplier of formal methods and digital twin software for railway signaling, headquartered in Stockholm.
Within the rail sector’s digital systems and software segment, Prover works at the safety-critical end, where interlocking logic must be proved correct before it enters service. Its signaling design automation suite consists of Prover Studio, Prover iLock and Prover Certifier, covering formal specification, application development and sign-off verification at safety integrity level (SIL) 4. Prover Trident is the company’s name for the three-phase process these tools support, not a separate product.
For each signaling project, Prover applies digital twin technology to build an executable model of the existing, future or conceptual interlocking system, using formal specifications and automated simulation to test the design before deployment.
Prover Extractor supports this by reading and analyzing legacy circuit diagrams, allowing older relay-based systems to be converted into digital models without manual re-engineering. The models are used for design validation, safety verification and stepwise migration planning, rather than for visual or predictive-maintenance purposes.
Market position
Prover holds ISO 9001 certification for its quality management system. Its Prover Certifier tool is approved by TÜV NORD as a CENELEC EN 50128 and EN 50716-compliant T2 tool for SIL 4 applications, the highest level defined in those standards.
According to the company’s own reference material, customers include Trafikverket, RATP, Infrabel and Stockholm’s public transport operator SL, alongside signaling suppliers such as Alstom, Siemens and Thales. The same source puts the customer base at more than 25 countries.
Alongside the Stockholm head office, the company has subsidiaries in Toulouse and in San Bruno, California.
Prover participates in industry bodies including UNIFE and IEEE, and has hosted the Signaling Design Automation Forum six times since 2018, in Stockholm, Paris and Shanghai, most recently in Stockholm in October 2025. No date has been set for the next edition.
Current activity
Cactus Rail secured a turnkey contract in 2024 for a new traffic management system (TMS) for the Stockholm Metro, and named Prover as a subcontractor in February 2025. Prover puts its own delivery at 62 stations on the Red and Blue lines, while a later project description on the same site gives the contract coverage as 64 stations.
The project replaces mechanical operator panels and non-vital relay logic with a computerized TMS and programmable logic controller (PLC) based control, while vital relay interlockings remain in place for safety-critical functions.
Prover’s role centers on modeling the existing vital relay interlockings across the affected stations, using Prover Extractor to convert circuit diagrams into digital models. These models support simulation of the new system’s behavior and generation of verified PLC logic ahead of physical deployment.
An earlier engagement with Stockholm Metro in 2021 and 2022 used the same approach to establish that the non-vital relays could feasibly be replaced with a PLC system, ahead of the current TMS rollout.
Prover has also worked with Trafikverket to formalize national signaling regulations into machine-readable requirements. In June 2025 it launched the Open Signaling Initiative, which promotes modular, multi-supplier signaling architectures intended to reduce vendor lock-in.
