Trains can travel between Christchurch and Invercargill again after KiwiRail and its contractors finished temporary repairs to a bridge damaged in a storm two weeks ago.
A concrete pier on the 610m-long Rangitata rail bridge was washed away on April 12, leaving the structure visibly sagging.
KiwiRail chief infrastructure officer Andre Lovatt said the temporary repairs had been “a significant undertaking”, but test trains had gone over the bridge and the regularly scheduled freight trains would continue tomorrow.
The repairs involved changing the flow of the river, building caissons – watertight boxes to enable construction – and installing a new structure beneath the bridge.
“We built a temporary support for the rail bridge, using a 250-tonne crane to push the four caissons deep into the riverbed and install and weld cross-bars into place,” Lovatt said.
Workers then replaced the tracks across the damaged spans, which had been warped when the bridge sagged.
“A huge thanks goes out to our civil contractors Paul Smith Earthmoving and HEB Construction, as well as KiwiRail’s structures (bridge) and track crews for their quick yet thorough work over the last two weeks,” Lovatt said.
He also thanked KiwiRail’s freight customers for their understanding and patience while the work was done.
“Though we have supported them with road-bridging options, I’m sure we all welcome the return of normal rail services, which will make freight movements more efficient and reduce the number of heavy trucks moving between Timaru, Ashburton and Christchurch,” he said.
Work to build a permanent replacement for the pier would begin now the line was reopened, Lovatt said. Designs had already begun and initial works would start next week, he said.
“Work will include driving new casings deeper into the riverbed and building a steel and concrete pier structure.”
KiwiRail would also look for the missing pier swept away by the river. Lovatt said it would well be buried in the riverbed.
He expected the permanent repairs to take up to 12 weeks.
The Rangitata River intersects with the Main South Line – the 601km stretch of railway between Christchurch and Invercargill – between the small towns of Ealing to the north and Rangitata to the south.
It is one of seven major rivers the Main South Line crosses. The river itself is about 120km long, beginning in the Southern Alps, traversing the Canterbury Plains and entering the Pacific Ocean about 30km north of Timaru.
Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.
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