Where a signalling design has implicit safety requirements that need to be validated onsite, field testers should be provided with comprehensive check notes and/or clearly annotated information that ensures specific testing requirements are not omitted.
As the re-signalling of Cootamundra neared completion it became necessary to undertake control table and software development concurrently to meet the targeted commissioning date. Normally control table and software development is done sequentially to ensure that all the control table logic is fully reflected in the final software and associated validation/testing processes.
The documentation and quality control processes used by the South Improvement Alliance for the Cootamundra re-signalling project were not sufficiently robust, in particular, the closing out of identified design issues was inadequate.
Where a design involves complex signalling arrangements, it may be beneficial to involve the designing engineer during the final onsite field testing phase as they have the best understanding of the interlocking principles. This places them in a strong position to identify any design omissions or deficiencies that may not have been evident during earlier phases of a project.
Regular monitoring and accurate measurement of rail creep was not carried out at the east end of the curve where train 6MB2 derailed in accordance with Civil Engineering Circular 3/87 - 70.2 and 70.3. Creep monuments were not installed on the east end of the curve following the work to convert the passing loop track to mainline operation in July 2008.
A record of the welds carried out at the 8.351 km point at Tottenham on the 30 January 2009 was not documented in accordance with the requirements of Civil Engineering Circular 3/87.
Punch marks were not made on the rail and documented with references to monuments at the 9 km mark following the realignment of track west of the Ashley Street rail bridge. This omission precluded the detection of rail creep that may have been present during the October 2008 maintenance inspection.
The section of track where train 6MB2 derailed, was previously utilised as the Tottenham standard gauge passing loop. It was not stress tested after slewing and welding when it was converted to mainline operation on 28 July 2008, 5 months before the derailment.
