Executive summary
This report examines 6 track heat buckle incidents that occurred in different localities throughout New Zealand in the summer of 2000/2001, 5 of which resulted in derailments. Safety issues identified by these incidents included:
• the need for training of track staff to ensure they recognise and respond to visible track defects
• the possible need to protect continuous welded rail, formed at an unknown neutral temperature, during hot weather
• the need to control tamping and lining to ensure track is not realigned leaving increased compressive stress in the rails
• the need to review the siting and trigger setting of heat sensors
• the practicality of the current Rule 176 regarding Caution signals for reduction of speed.
Five safety recommendations were made to the operator to address these safety issues.
[Safety recommendations 020/01, 021/01 and 022/01 were repeated in a subsequent report 02-104.]
Includes investigations 00-119, 00-120, 00-122 and 01-103
Related Recommendations
introduce alignment control procedures to ensure maintenance tamping does not result in an effective uncontrolled lowing of the neutral temperature of the rail. [SR repeated in report 02-104: 3 separate track buckle occurrences on the South Island coal route during the summer of 2001/2002.]
amend the Engineering Rules to ensure adequate warning of temporary speed restrictions is given to Les in a practical, effective and auditable manner until such time as the appropriate warning boards have been erected.
carry out specific training to ensure key track staff are aware of the vulnerability of sites that have an unknown neutral temperature, and the site deficiencies that justify inclusion of sites in "heat 40" lists. [SR repeated in report 02-104: 3 separate track buckle occurrences on the South Island coal route during the summer of 2001/2002.]
quantify lengths of CWR that have an unknown neutral temperature and ensure they are assessed, and protected where appropriate until destressing can be arranged. [SR repeated in report 02-104: 3 separate track buckle occurrences on the South Island coal route during the summer of 2001/2002.]
quantify the effectiveness of heat sensors at current settings to protect areas of weakness in hot weather, and if necessary lower the trigger levels of sensors in areas where buckling is occurring well below current settings.