A 610m-long rail bridge over the Rangitata River, South Canterbury, sags after flood water washed away one of 34 piers. Photo: Supplied / Allied Press / Connor Haley
All freight services going over the Rangitata Rail Bridge have been suspended after high flood waters washed away one of the bridge's 34 piers on Friday morning.
The 610-metre long rail bridge over the Rangitata River is an important railway linking Invercargill, Dunedin and Christchurch.
About eight freight trains travel across the bridge every weekday, and about five each weekend.
KiwiRail chief infrastructure officer André Lovatt said he was committed to keeping freight moving for customers and was working with those affected to find alternative options for them.
"We will continue to run rail services from the north to Christchurch and Ashburton and from the south to Timaru.
"Connecting rail freight will be managed using road bridging operations."
No passenger trains travel on the line south of Christchurch, he said.
Lovatt said there was a repair plan in place involving key engineering staff, contractors and KiwiRail's local bridge team but work could not begin until the river receded.
There have been inspections using drone technology and the data was being analysed in the meantime, he said.
"Tomorrow morning, once water levels have receded, we are planning a visual inspection and a further, closer drone inspection.
"These detailed inspections will confirm any damage to the bridge spans, any damage to other piers, and the repairs needed."
Lovatt said no repairs would start until it was safe to do so.
He was not aware of any other network damage caused by the recent weather events in the South Island.