The Scottish Government has unveiled plans to create a mass transit network in Glasgow and bridges or tunnels to some of Scotland’s islands.
The Glasgow Clyde Metro could better link 1.5 million people living in the West of Scotland, stretching around 15km from the city centre.
It is one of 45 core projects across the country which have been recommended for investment over the next 20 years, as part of the government's proposed transport strategy.
The ambitious project could see tram lines opened in Glasgow for the first time since the 1960s, alongside major upgrades to the existing rail network across eight local authority areas. Faster and more frequent trains linking the city centre and suburban areas would be created under a plan to introduce "heavy metro" services.
Transport Minister Michael Matheson said the multi-billion pound scheme would link people "from Clydebank to Cambuslang". It is estimated to take up to 30 years to build and cost more than £15bn.
He told MSPs that the second Strategic Transport Projects Review (STPR2) marked a "repositioning" of the government's priorities, with an emphasis on plans that will deliver environmental benefits.
However, the 20-year plan does not provide any funding commitments or timescales as part of its recommendations.
Among the ideas being explored are:
Electrifying more rail routes including the Fife Circle and Perth to Inverness route.
Improvements to the A75 and A77 road corridors in the South West of Scotland.
High speed and cross-border rail enhancements.
A feasibility study to replace ferry routes with either bridges or tunnels at the Sound of Harris and Sound of Barra.
Introducing more 20mph speed limits and zones, while creating networks of segregated freeways for cycling and walking.
Improving mass transit systems for Aberdeen, Edinburgh and Glasgow.
The transport strategy stressed the importance of continued work with the UK Government to "take forward a programme of infrastructure on-line and off-line upgrades targeted at longer-distance cross-border routes - these will provide higher speed passenger services and increased capacity and reliability for freight."
But the Scottish Government was accused of failing to provide details on when work will start and how much it will cost.
Labour MSP Pauline McNeil said: "Glasgow city region has not had a serious transport project under the SNP administration since 2007 and we desperately need one.
"The proposal for the Clyde Metro has no timescale, no serious funding allocated, and appears more of a concept in a document than a real transport project.
"I ask the transport secretary, when is this project likely to start - when will it be a reality?"
Matheson replied that it is built on work already carried out by the Connectivity Commission and the government will now look to put in place a programme of work.
"That involves us working with all the local authorities involved - not just Glasgow - and other partners in how we take this forward over a number of years."
Matheson added he could not give a specific time scale, other than it would happen within the next two decades covered by the transport review.
Greater Glasgow has the largest suburban rail network outside of London, but council leaders have argued that large parts of the region are still badly served by public transport.
A previous study recommended a light rail line should be built along the south of the Clyde to link Glasgow Airport, the Queen Elizabeth University Hospital, and the city centre.
Glasgow City Council leader Susan Aitken claimed the finished metro system could have "a bigger footprint even than Manchester’s Metrolink, the closest UK equivalent".
In a document published by Transport Scotland, the metro is defined as "one of, or a combination of, bus rapid transit, tram, light rail and metro rail".
It added: "These options would complement the service provided by traditional railways and may include the conversion from existing railways to tram or heavy metro."
Stuart Patrick, chief executive of Glasgow Chamber of Commerce, said that the business community will be looking for swift concrete implementation.
“Support is widespread across the city for improvements to transport links providing better access to businesses, education, employment and healthcare, and as the report shows the current offering is no longer sufficient.
“In particular a link between the airport and the city centre is vital to the economy of Glasgow, over £140m is available through the Glasgow City Region City Deal to make progress on this direct link, and it needs to remain a top priority for the Government.
“We look forward to supporting partners in their work to design and deliver the project phases as quickly as possible.”
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