ERA's Safety Engineering and Independent Safety Assessment (ISA) services cover all aspects of systems safety, from advice on Safety Management Systems and compliance audits to the provision of expert witnesses in litigation.

For example, ERA recently provided safety engineering expertise to facilitate the assurance process for new rail infrastructure equipment.The T72 point machine (manufactured by CSEE) and the VCC point locking mechanism (manufactured by Cogifer) are novel products to Network Rail Controlled Infrastructure, although they have been used widely elsewhere in the world.

A trial installation of T72/VCC equipment was commissioned at Cheadle Hulme Junction, south of Manchester, in October 2000. This work formed part of the Manchester South Capacity Improvement Project, undertaken by an alliance of companies comprising Network Rail, Ansaldo Segnalamento Ferroviaro (ASF),Atkins Rail and Amec Spie. Until 2003, the equipment interfaced with a free-wired relay interlocking controlled from Cheadle Hulme Temporary Signal Box. In April 2003, the relay interlocking was replaced by ASF's ACC interlocking, controlled from the new Manchester South Signalling Control Centre at Edgeley.

ERA was employed by Atkins Rail to support their safety assurance activities on behalf of the alliance. In particular, ERA staff were instrumental in developing the safety argument for the T72 and VCC, building upon work already undertaken by the alliance.

Of particular importance was the treatment of the T72 and VCC as part of a point operating system including the interfaces with the track and the ACC interlocking, rather than as standalone items of equipment. ERA developed a set of functional safety requirements, based upon consideration of the core functionality required for any system of point actuation, locking and detection on the railway.

Working closely with a points expert in Atkins Rail, the argument that the T72/VCC system achieves each of the functional safety requirements was developed. The argument drew on information from a wide range of activities, including the hazard analysis, EMC assessment, expert technical reviews of the equipment, signalling interfaces analysis, the safety case for the ACC interlocking and DRACAS data.

The safety case was reviewed by an Independent Safety Assessor prior to presentation to Network Rail's Professional Head of Signalling in February 2004. The safety argument was accepted. However, as recommended by the safety case, the points have remained under trial arrangements to resolve some outstanding performance issues.

ERA's Safety Engineering group has over 10 years experience o f independent assessment of safety related systems and is accredited to act as an ISA to Network Rail. The group has a broad scope of domain knowledge covering signalling and telecommunications systems, electrification, permanent way, rolling stock and safety related software.

For further information contact: safetyengineering@era.co.uk