The South Improvement Alliance engineers did not effectively identify and record that the interface between CA74C and CA74D was the fouling point between the Up Main line and No.1 Platform Road and thus did not recognise that the rear of a train sitting on the Up Main line at this location would foul No.1 Platform Road. The design deficiency was caused by a long standing practice of not explicitly recording the clearance point on the Signal Arrangement Plan, Track Insulation Plan or in the Control Tables.
Although the Australian Rail Track Corporation was not resourced to actively participate in the design or commissioning phases of the Cootamundra re-signalling project, greater involvement by the Australian Rail Track Corporation (local knowledge of site geography and layout) during these phases may have assisted the South Improvement Alliance engineers in detecting the design error.
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.
A design based on using a clearance point at the interface of CA74C and CA74D should not have been implemented until it was established that the clearance between the Up Main line and No.1 Platform Road at the interface of CA74C and CA74D tracks was adequate.
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.
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.
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.
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.
