All rail traffic on the Wairarapa line will halt for three days soon after Christmas for the switch to a new bridge spanning the Mangatarere Stream at Dalefield, near Carterton.
Structural engineer Michael Luke said work on the all-steel 32-metre bridge started in September alongside the old bridge, which had been standing at the site since construction in the 1940s or 1950s.
KiwiRail spokesman Mark Breslin said rail traffic on the line would stop for three days from December 27, while tracks were linked across the new waterway span, which is known as the Dalefield Rd Bridge or Bridge 65 on the Wairarapa line.
The new bridge will be in service from December 30.
He said commuter passengers would be taken to their destinations by bus over the three-day period.