Work to improve services for Wellington rail commuters passed an important milestone today with the signing of a $49 million contract to replace the overhead line system supplying power to trains on the Hutt Line.

The project involves replacing the existing poles with steel masts and renewing all the overhead wires, and replacing the system that supplies power to the signals and putting it underground.

"Replacing these systems is a big win for Wellington rail commuters," said KiwiRail chief executive Peter Reidy.

"It is vital for the resilience of the network.


"Our infrastructure teams work incredibly hard to keep things running smoothly but the current systems are reaching the end of their life.

"Without this replacement programme commuters would have faced increasing disruptions to the service as the wooden poles reach the end of their lives.

"The contract is part of a $98.4 million four-year project begun last year to replace the overhead power system between Wellington Station, Melling and Upper Hutt, as well as Ngaio and Johnsonville. The funding came from central Government.

The project, which will see 1274 existing poles and 38km of overhead wires replaced, is expected to be completed in 2021.

KiwiRail and Greater Wellington Regional Council are working together on the project.

The council's sustainable transport committee chairwoman Barbara Donaldson welcomed the signing, saying it was "a major step forward in improving our rail network infrastructure and ensuring a more reliable and sustainable service to people from the Hutt Valley who make five million journeys each year on the Hutt Line".

"Significant investment is needed on the infrastructure due to the ageing nature of the network and we are hoping for further investment to upgrade the rest of the infrastructure to unlock capacity and provide a modern, reliable service for all commuters in the Greater Wellington region," she said.