UIC IRS 90940 — SFERA Protocol: Train Operation Data Exchange with On-Board Devices

Scope

Defines the SFERA protocol, UIC's messaging standard for train-operation data exchange between infrastructure managers, railway undertakings and on-board devices, covering Driver Advisory Systems (DAS), ATO support data, Digital Instructions and free-text driver communication. The 3rd edition extends the original DAS-only scope into a universal on-board data-exchange protocol; download is free but requires a shop.uic.org account.

UIC IRS 90940 defines the SFERA protocol, UIC's messaging standard for exchanging train-operation data between infrastructure managers, railway undertakings and on-board devices, originally developed to support Driver Advisory Systems (DAS) that give drivers real-time speed recommendations to improve energy efficiency and punctuality. The 3rd edition extends the protocol's original DAS-only scope into a more universal on-board data-exchange protocol, adding support for Automatic Train Operation (ATO) support data, Digital Instructions sent from control centres to trains, and free-text driver communication messages, reflecting the growing range of digital services being delivered to and from moving trains. Infrastructure managers and railway undertakings deploying DAS, ATO or digital instruction systems use the protocol to ensure their on-board and trackside/control-centre systems can exchange this operational data using a common message format, rather than each project defining a bespoke interface. Downloading the specification is free of charge but requires a registered account on the UIC online shop, distinguishing its access model from UIC's paid technical publications such as IRS 70712. The current edition is Edition No. 3, dated February 2026.