External STM Supports Portugal’s ERTMS Transition

Hitachi Rail has been selected by Infraestruturas de Portugal to develop and certify a new External Specific Transmission Module (STM) for the Portuguese rail network. The project supports the country’s transition from its national CONVEL train protection system to the European Train Control System (ETCS) under the broader ERTMS migration strategy.

Enabling coexistence of legacy and European systems
The STM is designed to ensure interoperability between the existing CONVEL system and ETCS during the transition phase. As Portugal progresses toward ETCS deployment, trains will operate with both systems onboard, maintaining operational continuity on lines not yet fully upgraded.

This dual-system approach allows gradual implementation of ETCS Level 2 across the network while avoiding disruptions to existing services. It reflects standard European migration strategies, where legacy Class B systems remain operational until full interoperability is achieved.

Supporting phased digital signalling deployment
The introduction of an external STM enables integration without requiring fundamental redesign of onboard systems. By acting as an interface between ETCS and national signalling infrastructure, the module allows trains equipped with ETCS to operate on legacy lines.

This capability is critical for phased deployment, ensuring that infrastructure upgrades and rolling stock modernization can proceed independently while maintaining network-wide compatibility.

Strengthening competition and supply chain resilience
The development of a second STM for Portugal is intended to diversify the supplier base and reduce reliance on a single technology provider. By making the module available under fair, reasonable, and non-discriminatory (FRAND) conditions, the project supports a more competitive market environment.

This approach benefits railway undertakings and rolling stock manufacturers by providing greater flexibility in system selection and integration, while also supporting long-term maintainability.

Collaborative development across European teams
The STM will be developed through a collaboration between Hitachi Rail teams in Portugal, Sweden, and Italy. This structure combines local expertise in the Portuguese rail network with broader experience in European digital signalling systems.

Edited by Romila DSilva, Induportals Editor, with AI assistance.