Knowledge base
UIC 90940 SFERA
This article looks at SFERA as a protocol. It does not try to cover every implementation detail. It focuses on the main parts of the standard.
Published: April 5, 2026
TopicsUIC 90940SFERAStandardsInteroperabilityRailway information exchange
What the standard covers
- SFERA defines message format, authorisation model, and message patterns for DAS data exchange.
- It is built as a superset of the ERTMS or ATO Subset-126 approach.
- It supports S-DAS, C-DAS-C, and C-DAS-O.
Main message families
- B2G means Board to Ground. G2B means Ground to Board.
- The protocol uses requests, replies, and event messages in both directions.
- Common examples are handshake, Journey Profile transfer, Segment Profile transfer, status reports, and advice messages for C-DAS-C.
Why it helps
- It gives suppliers, operators, and infrastructure managers a shared technical language.
- It helps explain what data the onboard side needs and what the ground side must provide.
- It also makes cross-border and multi-supplier integration easier to structure.
Limits
- The standard does not remove the need for local agreements, local infrastructure data, and local operating rules.
- It also does not guarantee that every railway supports every mode at the same depth.
- That is why protocol compliance and operational readiness are not the same thing.
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