Railway bridge over Bealey River, Arthur's Pass National Park, going into Ōtira Tunnel. Photo: Getty Images / Gary Webber
A historic rail tunnel, which connects the West Coast to the rest of Te Waipounamu, is marking its centenary this year.
The Ōtira Tunnel opened in 1923 and travels close to nine kilometres through the Southern Alps to link Christchurch to Greymouth.
Tunnellers faced harsh conditions and used basic tools to break through wet shale and rotten rock while creating the steep track.
Current and former rail workers and community members joined a special commemorative TranzAlpine service along the route on Friday.
KiwiRail chief executive Peter Reidy said the Ōtira Tunnel was a testament to the hard work of staff.
"The tunnel remains a vital link on the Midland Line and a gateway to the West Coast. Each week, around 70 trains travel through the tunnel, carrying freight for our customers and visitors on TranzAlpine," Reidy said.
"KiwiRail connects West Coast producers with Lyttelton Port and overseas markets and provides a sustainable transport solution for the region's supply chain."
A considerable amount of work had been carried out to improve the safety and condition of the tunnel over the past four years, he said.