Transport Initiatives Edinburgh (TIE) shelled out part of the extra cash on equipment for a section of the line that is unlikely ever to be finished.
Jim Eadie, the SNP MSP who uncovered the figures, said the outlay was another sign of “financial mismanagement”.
Edinburgh City Council’s £545m plan to reintroduce trams to the city, delivered through arms-length firm TIE, has been marked by delays, cost overruns and crippling disputes.
A transport link that was supposed to stretch between the city airport and Newhaven has now been radically scaled back.
By May this year, £440m of the original budget had already been spent, despite around 72% of the project remaining unfinished.
Councillors then approved a plan for a much shorter route, ending at St Andrew Square, which would cost a bumper £773m.
However, a question mark hangs over this ambitious commitment as the council does not yet have a plan for filling the £228m black hole.
Despite the impasse, it can be revealed that another £38m of the original £545m budget was spent by TIE between May and July.
A chunk of the money was used to buy equipment and materials for the purpose of extending the tram line to Newhaven. The assets will be stored until this part of the project is given the go-ahead.
However, the Sunday Herald has struggled to find anybody outside TIE who believes the trams will ever go to the northern tip of the city.
Another part of the £38m was associated with the trams contractor restarting work on three parts of the project: the Gogar depot; the A8 underpass; and Haymarket.
Of the £478m spent so far, £261.8m was used on tram infrastructure and vehicles.
Around £70.4m was spent on utility diversions, £32.9m on “design”, and £21.3m on land and compensation.
A further £91.9m was doled out on “resources and insurance”, which includes staff, legal and consultancy costs.
Eadie said: “The public will rightly demand to know how much of the £38m has been spent on a mythical tram line that is effectively a line to nowhere. They will also rightly demand to see the business case for this extra spending.”
John Carson, who is standing as a ‘Stop the Trams’ candidate in next year’s council election, said: “This is further proof that the project is out of control. I don’t understand why we are spending another £38m when there are no extra funds available. It’s outrageous.”
A spokesman for TIE said: “Expenditure on the project since mediation has been as a result of the remobilisation of work on priority areas of the tram route including Haymarket, the Gogar Depot and the A8 underpass and any physical progress made to date in these area.
“The decision to purchase all systems equipment as part of this agreement was made in order to safeguard these assets for the future extension of the line to Newhaven.”