The Auditor-General has decided not to investigate a deal between KiwiRail and an overseas manufacturer.
Labour MP Clare Curran asked last year that the Auditor-General look at the purchase of freight wagons from China Northern Locomotive and Rolling Stock Industry Corporation.
KiwiRail went with the Chinese firm because its price of $31 million was the cheapest.
KiwiRail's own workshops in Dunedin at the time put in an unsuccessful tender for $37 million.
Ms Curran requested the Auditor-General look into the value for money of the deal and the affect on the Hillside workshops, which were bought by an Australian company last year.
The Auditor-General's office says KiwiRail made the decision for normal business and commercial reasons and was not influenced improperly.
The Rail & Maritime Transport Union said an inquiry would have been helpful.
General secretary Wayne Butson said an aspect that needs to be assessed is whether KiwiRail considered its obligations as a state owned enterprise operating for New Zealand's best interests.
