The £162m Northumberland Line rail project is set to bring passenger trains back into service between Ashington and Newcastle.
Aecom and SLC Rail have been working on plans for the county council since 2018.
The county council is now looking for a contractor to build the six stations on a framework basis. New stations at Northumberland Park, Newsham, Bedlington and Ashington are in phase one of the project, with construction work expected to start in summer 2022.
Additional stations at Seaton Delaval and Blyth Bebside are in phase two, which could start in 2024
The scope of the £40m stations contract includes the construction of six stations and car parks, including associated infrastructure.
The tender documentation can be obtained from www.procontract.due-north.com reference number DN532422.