The rail system is being rebuilt to the benefit of the national economy with a new maintenance hub in Christchurch and a full fleet of replacement locomotives for the entire South Island, Rail Minister Winston Peters says.

"The South Island has hauled goods from the hinterland to coastal ports since the first track was laid in Christchurch in 1863 and vastly expanded by Julius Vogel from the 1870s, and we are rebuilding rail for the benefit of the national economy today," Mr Peters says.

"Today we have launched the fully rebuilt and upgraded Waltham Mechanical Hub in Christchurch and the first of 66 new DM Locomotives, both thanks to investments we committed in 2020.

"While others paid lip service to rail, we put the hard work in on the back of a democratic mandate and rebuilt an industry that generates at least $3.1 billion in economic value every year - with the South Island alone receiving $1.2 billion since 2019 for rebuilt workshops, new locomotives, and large-scale rebuilds of the network infrastructure.

"New DM Class locomotives will bring vastly superior fuel economy, hauling power, and have cabs at both end to simplify yard movements - all contributing to lower costs to serve customers and lifting schedule reliability.

"We are now seeing the benefits with KiwiRail reporting a $73 million half-year profit, schedule reliability improving, and rail freight volumes increasing by 7 percent when road freight volumes lifted by 2 percent - indicating market share shifting from road to rail.

"We want to see every asset built by the taxpayer generating value - including road and rail - and this is what is now happening," Mr Peters says.