Plans for a north-south Edinburgh tram line that could take passengers from Granton to the city centre via Orchard Brae and out into Dalkeith are set to be considered by the council early next year.
The proposed extension is central to plans for a 'mass rapid transit corridor' to reduce congestion and streamline public transport across south-east Scotland to meet the needs of the region's growing population.
If approved it would double the length of the existing line, including the new section through Leith which is due to open in the spring.
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And the council said it will make the case for it to be considered as a piece of national infrastructure - meaning the Scottish Government would meet the cost.
As work on the Newhaven line nears completion in February, city councillors will be presented with a new public transport action plan setting out options for a line from Granton to the city centre and then towards the Royal Infirmary and Edinburgh BioQuarter.
Potential future tram routes beyond this, included in a map published by the council, show extensions to link up with Sherrifhall park and ride, Newcraighall and Shawfair's train stations and into Dalkeith in Midlothian.
However, expansion of the network beyond the city's boundary is likely to be many years off, with current estimations indicating the Granton to BioQuarter line would not be open until at least 2032.
This would be completed by one contractor in two phases - Granton to city centre and city centre to BioQuarter - although it is not yet known which would come first.
In Edinburgh's original tram plan, before the project was scaled-back amid huge delays and soaring construction costs, the second phase was intended to deliver a new track from from the city centre to Granton via Roseburn, Ravelston and Craigleith.
However, transport chiefs are now eyeing-up a 'preferred' alternative route through Orchard Brae and Crewe Toll, turning right at the end of Princes Street instead of continuing to Haymarket, as this would serve more residential areas.
It is also understood this is seen as a better option by the council as it would avoid Roseburn, which is being developed as a major walking and cycling route.
But it would pose serious challenges of its own for engineers as it's unlikely tracks could be laid over The Dean Bridge.
Edinburgh City Council's transport convener Scott Arthur said: "Roseburn is attractive because it's a former railway line, but there are accessibility issues there.
"Whereas this newer route goes right through residential areas and may connect better for people.
"We'll listen to residents on which route we should pick but we're committed to delivering the biggest ever expansion of public transport in Edinburgh.
"We're making the case to the Scottish Government for this being a piece of national infrastructure. And that means they start to think about funding it and that's really important."
He added: "We're committed to net zero and cutting congestion and the blueprint for sustainable public transport in the circulation plan will be the foundation of that transformation."
No estimate has been given for the cost of the proposed expansion. Construction of the initial tram line was marred by controversies after the total price reached £776m - more than double the original estimate of £375m
A public inquiry sparked by the failures, which is still to release its findings eight years after it was first announced, has also gained notoriety for its £13m price tag - the same as the Chilcot Inquiry into the Iraq War.
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