The fire-damaged railway line linking Christchurch and Greymouth is to reopen ahead of schedule on 20 March.
The Midland line was badly damaged when a fire swept through 300 hectares between Cass and Springfield over Waitangi weekend, damaging several bridges.
Twelve wooden piles needed to be replaced on one bridge.
Initial estimates were that the repairs would take at least six weeks, and KiwiRail had been expecting to re-open the line in early April.
KiwiRail spokesperson Todd Moyle said the line was used by the TranzAlpine tourist train, and also for shipping coal and dairy products from the West Coast.
The line would initially open for freight, with the TranzAlpine service expected to resume shortly after.