The major refurbishment project was finished ahead of schedule and Transport Minister Humza Yousaf joined engineers to see the project's early completion.
The 20-week scheme has involved renewing 1,800 metres of concrete slab track and installing over 4,000 metres of new rails.
Nearly 3,000 engineers worked on the project, which forms part of the Edinburgh Glasgow Improvement Programme (EGIP) to electrify the main Edinburgh-Glasgow, via Falkirk High line.
Work will continue over the next three years at Glasgow Queen Street to extend the station out towards George Square and create a new concourse and passenger facilities.
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After helping to tighten the final bolt on the new slab-track, Minister Yousaf said: "I am pleased to see the work on the Queen Street tunnel completed ahead of schedule and on-budget.
"This has been an unprecedented project, both in engineering terms and in the scale of the operation required to keep people moving and services diverted via the underground platforms during the works.
"This is a key milestone in our programme of investment for Scotland's railways and literally paves the way for the introduction of a new generation of electric trains."
Phil Verster, Managing Director of the ScotRail Alliance, added: "This was a massive engineering challenge and it was only through the careful planning and professional delivery of the project team that we have been able to complete this vital investment in Scotland's railway ahead of schedule."
The redeveloped Glasgow Queen Street station is due to be completed in 2019.
(LM/JP)
