The upgrade of what is the third oldest metro system in the world will result in a state-of-the-art underground with driverless trains.
Glasgow's Subway system opened in December 1896 and now carries around £13million passengers each year.
The most expensive element of the upgrade will be buying new trains, signalling, controls and sliding doors on the platforms.
A report to SPT this week states: "The overarching operational requirements are for a fully automated driverless system that provides more frequent, reliable and flexible service to our customers, while also reducing on-going operation and maintenance costs."
Work on upgrading the Subway at Partick Interchange was finished on programme and on budget.
Ibrox station is completed and re-opened in January this year. Work on Kelvinhall station began in March last year and finished recently.
In January this year, the upgrade of St Enoch station began ahead of schedule and designs for Govan and Buchanan Street stations are nearing completion.
Work on Buchanan Street will start once St Enoch is finished to minimise the impact on city centre commuters.
It is hoped the upgrade of Bridge Street, Cessnock, Shields Road and Kelvinbridge stations will start this year and be finished by 2015.
The installation of 11 out of 28 new escalators has been completed, the most recent at Govan and Kelvinbridge, while new smartcard tickets went live on November 11 last year with almost 18,000 personalised cards issued.
The report states: "The vast majority of card applications have been made online and SPT staff continue to process around 100 card applications a day."
A number of contracts awarded last year to improve priority sections of the infrastructure are now finished.
These include tunnel water sealing works in various sections between Kelvinhall and Partick, tunnel lining and water sealing works between Buchanan Street to Cowcaddens and phase two works at Broomloan yard.
The report states: "Overall, the Subway modernisation programme is progressing well and all work streams are within the overall timeline for completion and budget."