KiwiRail says it plans to thoroughly investigate the cause of a goods train derailment in the Picton railyards on Saturday morning.
The second locomotive of the train tipped on its side and a wagon went partly off the track at about 10am.
The incident caused delays to goods trains and vehicle traffic until the line was cleared at about 1.30pm.
A KiwiRail spokesperson, Kevin Ramshaw, says it will take some time to find out what happened.
The driver was not injured.
