Track checks needed
An investigation into the derailment of a logging train in Palmerston North has found Kiwirail had no procedure for finding and fixing a specific safety problem with its tracks.
The inquiry also found a combination of factors, including speed, contributed to the derailment that closed the North Island Main Trunk Line for almost a day.
The Transport Accident Investigation Commission released its final report yesterday into the derailment on April 4 last year.
The freight train was carrying logs from Palmerston North to Napier, but derailed near the Railway Rd overbridge.
The crash cost Kiwirail $661,000, including $257,000 to fix the line.
But the commission found a range of issues at play.
The train was travelling at 25kmh, the maximum speed, but the driver applied more power while the train went down a descent.
The train got to 32kmh before there was a sudden loss of brake pressure.
There was insufficient weight on the leading bogie, or wheel frame, of a log-carrying wagon to keep it on the track.
The track also had several cyclic track twists — when the two rails the train travels on are at different heights to each other — leading to the crash.
The suspension system on one bogie had two broken springs, with the corrosion near the breaks showing they likely snapped before the derailment.
Although they had been checked during visual inspections, the broken bogie had not had a full overhaul since March 2007.
The commission also found Kiwirail had no procedure of identifying, evaluating and fixing track twists such as the cyclic ones leading up to the crash site.
The commission recommended Kiwirail develop a way to identify cyclic track conditions and work out a process to figure out when they might cause derailments.
The commission said in its report Kiwirail was working on a procedure for finding and fixing track problems.