The first new locomotives to arrive in New Zealand in nearly 35 years will land at the Port of Tauranga this week, another step in the country's multibillion-dollar rail turnaround.

Six of 20 new diesel locomotives on order at a cost of around $80 million are due to be offloaded at Tauranga towards the end of the week. They will be towed to KiwiRail's Te Rapa base in Hamilton for commissioning.

The engines were built by China's Dalian Locomotive and Rolling Stock Co, with the other 14 due early next year, a KiwiRail spokeswoman said.

The new engines will be initially used on the Auckland-Hamilton-Tauranga "golden triangle" run and Bay of Plenty forestry routes.

They will enable KiwiRail to free up a second locomotive used on services that currently require two "back to back" engines.

The double cab locomotives have 2700kW engines, with similar pulling power to the electric locomotives in use on the North Island main trunk line. They should be 5-10 per cent more fuel efficient than a current fleet engine, and where they replace two locomotives, the fuel saving will nudge 30 per cent.

The youngest engines in KiwiRail's current diesel fleet were bought in the early 1970s.

The state-owned enterprise is ending the first year of a 10-year $4.6 billion turnaround plan. Taxpayers will give it a shunt with a $750m capital injection in the first four years – providing KiwiRail offers the Government a convincing business plan each year. The balance of the $4.6b must be earned by the company.

- © Fairfax NZ News