KiwiRail is concluding the sale of a major part of its Hillside workshops in Dunedin to a global metal-casting company.
The state-owned enterprise put the 130-year-old railway workshops on the market in May, expecting to sell them by August, but the deal has been delayed.
An announcement on the sale is expected on Tuesday but Radio New Zealand has been told Australian-based industrial firm Bradken is the main purchaser.
The international company already operates a metal foundry in Dunedin and sources say it would expand its operations by taking over Hillside's larger casting facility.
However the deal is for only part of the large South Dunedin site, and appears not to cover the train fabrication and project workshops.
KiwiRail is expected to maintain access to the site's heavy lifting crane.
The fate of Hillside's 120 workers is not clear.