The work will see the main entrance at George Square replaced by a huge glass facade. The stations platforms and concourse will also be extended to accommodate the faster, longer, greener electric trains being introduced as part of the £742m Edinburgh-Glasgow Improvement Programme (EGIP).

The transport hub handles 20 million passengers a year but this is predicted to grow to 28 million passengers by 2030.

The redevelopment is expected to be completed by 2019.

Features of the scheme will include:

Once the tendering exercise is complete, the contract will be awarded in autumn 2016.

Work to upgrade the track in Queen Street Tunnel will then begin in late March 2016.

Although the tender is being issued by Network Rail, the project will be overseen by ScotRail Alliance - a management team created from senior Abellio ScotRail and Network Rail staff for the purposes of overseeing major projects in Scotland.

MD of the ScotRail Alliance, Phil Verster, said: “This is another tremendously exciting step forward in our plans to transform Scotland’s railway. We recently announced our largest ever Train Improvement Plan, which will deliver new trains, thousands of extra seats and great facilities such as at-seat power points and enhanced Wi-Fi across our fleet.

“Today we are confirming that one of our busiest and most important stations will also be transformed, making it larger and with much better facilities for our growing number of customers.”