The CBTC User Group - discussing the CBTC signaling systems of today and tomorrow

Together with the metros of Copenhagen (Metroselskabet, MS), New York City (New York City Transit, NYCT) and Stockholm (Storstockholms Lokaltrafik, SL), Prover has founded the CBTC user’s group to share experiences and best practices in the area of Communication-Based Train Control systems (CBTC). The inaugural digital meeting was held on March 11, with presentations from the members and discussions on the future of the group.

The idea is to expand the group to include other metros that have an interest in sharing knowledge and best practices regarding the CBTC signaling systems of today and tomorrow. There will be quarterly meetings focusing on different relevant topics, with presentations from the members as well as from external experts. The group enables and catalysts on-going discussions and knowledge sharing between the metro´s given the relationships and network that gets established.

A common interest in the CBTC User Group is the use of formal specifications and methods to reduce costs for system development and safety assessments, by enabling more automation and increasing competition. It becomes a means for the infrastructure managers to gain further control of their systems. A common view raised during the meeting is that the cost of ensuring safety is high, but it can be reduced by structuring and formalizing data, thus establishing a solid process with formal methods from the start of the project, to avoid late surprises and delays during the safety assessment process.

Metroselskabet gave an overview of their driverless metro systems, which includes both state of the art CBTC as well as an older, more traditional system. They see delivery, safety approval and maintenance of software-intensive signalling systems as a challenge today, with room to improve with a more formal approach. It is important to reduce on-site testing, especially for brown-field projects; the metro in Copenhagen, as in New York City, operates 24/7. Formal methods are considered an essential component in the work to reduce on-site testing.

SL presented their organization and its objectives, and how they envision the use of formal methods and COTS components in future signalling systems to give the Infrastructure Manager better control of their systems. SL has a diverse set of signalling systems in their network and are currently making up the plans for the re-signalling of the entire subway system.

NYCT gave an overview of their interoperability specifications for CBTC systems, which enables them to have full interoperability between the on-board and wayside equipment from three different suppliers. They also presented their plans for introducing the novel train localization technology Ultra-Wide Band (UWB) and how that will affect their systems and the interoperability. UWB is expected to bring many benefits for the CBTC roll-out, with simplified installation requiring less interruption to the traffic compared to traditional localization technology.

Is your metro interested in joining the group or do you just want more information? Please get in touch with us at

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