THE total overhaul of one of Scotland's busiest railway stations has been given the formal green light, a move expected to trigger major city centre development.

Glasgow's £100million-plus Queen Street Station revamp had been hit with significant delays due to major contractual and legal wranglings.

But the required Government authorisations, knows as TAWS orders, which had been eight months behind schedule, have now been signed off.

The work, expected to completed by 2019, will include provision for longer trains and capacity for the station to handle increased passenger numbers, as well as new retail and leisure outlets.

The move comes just three days after Network Rail said it was in the dark over when the TAWS orders would be completed, meaning it could not commit to when work would start or end.

Transport minister Humza Yousaf told MSPs on Wednesday he expected to approve them within 48 hours although warned those objecting to the TAWS orders had the right to seek further legal recourse to potentially hold the scheme up.

The sign-off will trigger the preliminary works needed for the similarly delayed redevelopment of the neighbouring Buchanan Galleries shopping centre, which is tied in with the Queen Street plans.

But the completion date here is likely to mean the railway station's retail offerings may not be in place for several years after the structural works are done.

Mr Yousaf said: "The Scottish government is delivering the most ambitious programme of rail investment ever seen in Scotland, committing over £5bn across the current funding period.

"Approval of this Taws Order allows Network Rail to undertake significant enhancements to Glasgow Queen Street Station.

"This continued investment in our key rail hubs will not only accommodate longer trains and the future growth in passenger numbers, it will also improve the overall service experience."

He added: "Coupled with new longer, faster, greener Class 385 trains coming later this year and a full fleet refurbishment, we are doing what we can now to deliver a Scottish rail industry for the future, one which encourages even more people opt to get out their cars and onto trains."

Glasgow Chamber of Commerce chief executive Stuart Patrick said: “We welcome the granting of the TAWS order for Queen Street station. It is an important step in bringing forward important city centre development.”

Network Rail said the revamp was needed to meet predicted growth to 28 million passengers by 2030, eight million up on current numbers.

The project is part of the Scottish government's £650m Edinburgh Glasgow Improvement Programme (EGIP), which aims to reduce journey times and increase capacity on Scotland's main rail routes.