Work on improving the North Auckland line, which was in a poor state after years of under-investment, began only a year ago, he added, the project including replacing five bridges and lowering the tracks in 13 tunnels in just seven months, to allow the passage of hi-cube containers, standard for international shipping, in and out of Northland by rail.
"In the tunnels, KiwiRail built on the experience and relationships forged in the Kaikōura recovery, and included tested construction firms and key individuals from the outset," Miller said.
"All the bridges have the same modular design, which gave us economies of scale and speed in construction.
"In addition to lowering the tunnels, we undertook essential repair works. As we progressed, it became apparent that had this major investment not been made, the line would have closed."
All the new and rehabilitated structures had clearance through the tunnels for electrification to be added later, which helped to further improve the network's resilience over time.
"We procured, designed and delivered the project in a year, which is an extremely short timeframe for such a large-scale, complex project," he added.
"At its peak, more than 600 people were working on the project at one time. In addition to the new bridges and improved tunnels, the team laid 30,000 new sleepers and nearly 63,000 cubic metres of ballast to provide a more secure base for the track.
"Throughout the project we created employment in Northland for everyone from new trainees to skilled professionals. For example, local firm Busck supplied sleepers and prefabricated bridge sections, and United Civil was the lead contractor on some bridges and some tunnel works.
"Delivering the re-opened line on schedule is a major achievement, and I acknowledge the project team, crews and contractors who've worked incredibly hard to make this happen."
More than 400,000 hours went into the construction phase of the project, which marked its completion with the running of a test train last week carrying trial hi-cube export size containers. The train ran successfully along the length of the line, following an early morning blessing in Whangārei, and by late last week freight trains were again running.
"While we are delighted that this section of the line is up and running, some more intricate work to the tunnel linings is required," he added however.
"Additionally, to allow greater train speed and axle weight, over time we will be replacing another 10km of rail and laying more than 100,000 sleepers."
And while KiwiRail did not yet have a spur directly to Northport, the PGF funding had allowed it to begin buying land along the route.
With freight volumes in the region expected to increase from the current 18 million tonnes a year to 23 million tonnes by 2042, rail would be a crucial part of developing an efficient, integrated transport system for Northland. Across New Zealand, the company was working hard to support importers and exporters, and to increase its share of the freight market.
Meanwhile the re-opening provided an opportunity to remind people to take care around the railway line, and to always look for trains before crossing the tracks.
