SWEDEN: Stockholm transport authority SL has licensed iLock software from local company Prover Technology to use when creating its interlocking requirements.

Running on a standard PC with a drag-and-drop editor or by using imported files, iLock draws on a formal specification library defining the general principles for Swedish interlocking systems, adapted to SL's needs. The configurations and requirements are then generated and the resulting data automatically checked. The output is exported in standard formats for use in the automated development of interlocking software or analysis of an existing interlocking.

So far iLock has been used for computerised interlockings on the Roslagsbanan commuter line and relay-based systems on the Saltsjöbanan.

‘Introducing a standard process for generating requirements will improve communication with suppliers and contractors, and provide a formal interface for the signalling system planning process’, according to Arne Borälv, CEO of Prover Technology. ‘This deployment is yet another sign that the industry is moving towards increased use of modern engineering processes and tools.’