SHOPPERS in Edinburgh's Princes Street may glance across the closed-off roadway to find it deserted apart from red and white barriers, portable buildings and works vans.
But behind the fences and along a 11-mile swathe of the city, the Scottish capital's tram line is taking shape, in a project involving more than 700 workers.
The project, which officials describe as on a par with the Forth Bridge and the most complex project in Scotland for a generation, has been beset by problems and delays – the latest being the construction company admitting for the first time a key piece of work is behind schedule.
The agency behind the tram project, Transport Initiatives Edinburgh (TIE), said the tram depot at Gogar, near Edinburgh airport, could be up to nine months late.
The company was forced to admit the delay after questions were lodged under Freedom of Information legislation.
The fresh delay comes on top of new TIE chief executive Richard Jeffrey's recent admission that the project might not be finished by July 2011 and could run into 2012.
However, for now, across the city centre are the first tangible signs of the impending return of trams to Edinburgh after nearly 53 years.
Passengers on the main Edinburgh-Glasgow railway line are also seeing evidence of the 545 million scheme taking shape over the largely off-street half of the route, west of Haymarket, where bridges and earthworks are visible.
A viaduct is under construction beside Haymarket station to bring the tram line from road to rail level, but building has been delayed by prolonged work to trace an unrelated gas leak and the redesign of a retaining wall following the demolition of the Caley Alehouse.
Further west, diggers are preparing the route beside Carrick Knowe golf course, while there is foundation work on a new bridge and preliminary work on the former guided busway in Stenhouse.
Just west of Edinburgh Park station, a seven-span viaduct over the railway line is on schedule for completion in September or October.
North of the Gyle, an underpass taking trams under the A8 is being built, which will see a 70ft new section of the road running over its roof. Traffic diversions will continue until the structure is complete next year.
To the north of the adjacent Gogar roundabout, foundations are about to be laid in a huge water-filled hole that will become the tram depot.
Work has already been delayed by "challenges" such as the relocation of major gas and water pipes, along with sewers, which were not originally included. The setbacks mean there is now a race against time to get the depot ready before the first trams arrive from Spain for testing in April or May next year. Test runs on a one-mile section of the route to Ingliston would follow later in 2010.
Tram project director Stephen Bell told The Scotsman: "I would expect the depot to be able to house the first tram at that time. It will not be finished, but we will be able to start testing."
However, he said the precise timescale for the work – and the rest of the project – had still to be agreed with the construction consortium following resolution of a dispute over work in Princes Street in February.
Back in the city centre, drivers have already had their patience tested for two years, as essential preliminary work to divert a complex web of underground pipes and cables continues.
The good news is that the work is nearing completion, with 80 per cent done and the remainder due to be finished by September – nine months late – other than at Edinburgh airport and near Leith docks. Six sites are still being worked on, at Haymarket, Shandwick Place, the Mound, St Andrew Square, Leith Walk and Constitution Street in Leith.
However, the bad news is that tram-line construction could bring the worst traffic disruption yet when work starts in Picardy Place next year for up to 12 months. The crucial roundabout at the top of Leith Walk will become an enlarged circular one-way system.
Mr Bell admitted the site would be "the hardest place to deal with" because of its location, and detailed discussions are under way with the police and Lothian Buses in an attempt to minimise the impact.
He said: "It is the area which will see the greatest changes to traffic, and one of the hardest for us to see a straightforward solution. However, we will make sure we get it right in the way that we have got Princes Street right." Details are due in August.
The west end of Princes Street saw the first tram tracks being laid earlier this month, with the work – currently running one month late – continuing east as far as Waverley Bridge by the autumn. Track laying is also due to get under way in Shandwick Place and on the former guided busway in August, and on Leith Walk in September.
EDINBURGH TRAM ROUTE
THE 14-acre site – about the size of Murrayfield stadium – will house the 27-strong tram fleet. Foundation work is about to start. However, delays caused by pipe diversion work will mean the complex will be only partially finished when the first tram arrives there for testing next April or May.
A HUGE new embankment, up to 13ft high and stretching from Roseburn Street to Balgreen Road, will carry the tram line past Murrayfield stadium and above homes in Baird Drive. Alterations to the Murrayfield Wanderers' clubhouse and repositioning of some stadium turnstiles will be required.
TRACKS started being laid earlier this month between South Charlotte Street and Castle Street, and will extend east to Frederick Street by next month. The work will continue over the Mound junction, where a 120-year-old cast-iron gas main has been replaced. The work is to finish in November.
TRAM-LINE construction in Picardy Place could cause the greatest disruption of the whole project because of its location on the city's traffic network. Work will not start till next year after Princes Street has reopened because of a cap on the number of city centre road closures at one time.
TRADERS and residents in Leith Walk who have endured two years of roadworks while pipes and cables are moved have been promised a respite in August – but disruption will resume in September when tram-line construction gets under way. The diversion work should be finished next month.
TRAM body shells are taking shape at manufacturer CAF's factory in Spain and the first test-track trials are due later this year. The first tram is due to arrive in Edinburgh next April or May, for test runs.
Five of the 27 trams should be delivered by next summer and the rest by mid-2011