A key report published today spelled out an updated business case for the project – but stops short of recommending that councillors approve plans to extend the network.
Three potential options have been set out, with extending the line to Newhaven budgeted at £144.7m. Taking the tram to Ocean Terminal would cost £126.6m, while extending the line to the foot of Leith Walk costing £78.7m.
These figures will be tested, with firms interested in bidding for the contract asked to provide their own estimates.
City chiefs confirmed that they would ask the Scottish Government to help fund the project if it is approved by councillors, despite the SNP at Holyrood insisting that “not a penny more” would be spent on Edinburgh Trams.
Officials are desperate to avoid a repeat of the financial and construction woes which dogged the building of the current line from Edinburgh Airport to York Place.
It will now be autumn before councillors make a final decision on the plans – with a September deadline for the audit, which will also include “market research” among building firms to give councillors “real-world information” about what the total bill could be.
Initial estimates will be scrutinised at a full council meeting next week, however a short extension to McDonald Road has effectively been ruled out as not being cost effective.
The News understands that SNP councillors are pushing for a decision in November in order to allow up to two months to consider the responses of interested firms, while Labour would prefer an October decision.
Extending the line to Newhaven was priced at £80 million when the network was first proposed, but updated costings were ordered in December.
City transport convener Lesley Hinds said: “It is essential that we learn from our past mistakes and I am confident that this process will deliver thoroughly researched, strategic options for a tram extension.”
John Hein, convener of Leith Central community council, said he understood why councillors needed more time to consider the case, but added that residents wanted a decision soon.
He said: “It sometimes feels as if we’ll all be dead before we see a tram at the bottom of Leith Walk. The sooner this can be decided, the better.
“I think it’s one of these things where, five years after the tram has arrived, everyone will think they’re absolutely wonderful, but it’s a nasty process when things are being dug up.
“That said, if a delay of a couple of months would mean that it would be done properly this time, then so be it.”