BBC Scotland news website, Edinburgh and East reporter
The latest phase of the work that will lead to the creation of Edinburgh's transport "backbone" is getting under way in the Scottish capital.
Works on Leith Walk are causing disruption to drivers
Several roads in the city have already gone under the knife as part of the construction project to create a new 16km tram route.
Constitution Street is the latest area to be affected, with the start of works which will see sections of the street closed for nine weeks.
It is all part of the £498m project to construct line 1a, otherwise known as Edinburgh's "backbone", which stretches from Newhaven to Edinburgh Airport.
The project has been spoken about since the turn of the millennium and has been about seven years in the planning.
But now the work is well under way, with roads closed and contraflows put in place - affecting everyone from motorists to businesses to rugby fans travelling to Murrayfield Stadium.
That disruption is set to continue as the roadworks expand into new areas to prepare the ground for the project.
As one official said: "We have had the canapes, but now we are entering the guts of it - with starters, main course and dessert to come."
Before the tram tracks can be laid, pipes, cables and wires have had to be moved from underneath the tram route.
Work will run almost continuously until the project is completed by early 2011.
STREETS AFFECTED BY WORKS
St Andrews Square
Edinburgh Park Station to Forrester High School
Union Street, Gayfield Street and Picardy Place
South St David Street
Work has been under way in Ocean Drive, Leith Walk and Roseburn since last summer, carried out by contractors Alfred McAlpine.
Five months of utility work started in Shandwick Place on 1 March.
It is due to finish in time for the Edinburgh Festival. The road is expected to re-open in August before a contraflow is set up so work can start on laying tram tracks.
Works due to start in May will include Ocean Terminal and Haymarket Station to Roseburn Sub-Station.
The tram infrastructure work, to be carried out by Bilfinger Berger Siemens (BBS) will start in April. This will overlap with the pipes move.
Between April and June there will be excavation and site clearance of Russell Road Bridge; demolition of the Caledonian Ale House at Haymarket junction; and tree felling and site clearance between Murrayfield Stadium and the railway.
It is understood that Princes Street will be completely closed to traffic for more than a month in 2009, and that there will be disruption along the route for the next three years.
The funding is in place for line 1a, which has a budget of £498m.
A spur from Haymarket to Granton, known as 1b, was put on hold when the tram plans were scaled back in 2006 amid fears that costs were spiralling out of control.
Transport Initiatives Edinburgh (Tie) has now secured a fixed price of £87m to build the 1b line, if it can commit to the project before next spring.
Although the line has the green light from the Scottish Government, it cannot go ahead unless Edinburgh City Council gives approval to a business plan.
A second tram line has been proposed, which would complete the loop between Granton and Newhaven and extend the first line from Ingliston to Newbridge. However, it has not been given the go-ahead or funding.
Although business and retail leaders believe trams will be good for Edinburgh, some have been feeling the impact of the roadworks on their takings.
The Small Business Support Scheme is a £2m pot which was created in 2007 to help compensate firms for loss of revenue from lack of footfall due to the disruption.
As of 14 March, just over £500,000 had been given to businesses. They receive a one-off payment of £4,000, as well as help with tax rebates.
The construction phase will employ 1,000 workers and the trams themselves are expected to create 930 new jobs.
Ninety drivers will be needed to run the 27 Caf trams, which can hold 250 people. They are currently being built in Spain.
The drivers will start being employed from October 2010, with both bus and train drivers being targeted during the recruitment process. They will be trained on a piece of ground at the Gogar depot.
Neil Renilson, the chief executive of Lothian Buses, will run Transport Edinburgh Limited, which will oversee both buses and trams.
He said it would mean trams working alongside buses rather than in opposition.
There will be an integrated ticket, with a one-off payment for a journey which can be used on both modes of transport.
There are presently 650 Lothian buses on the road in Edinburgh, and that figure is expected to drop by just 19 when the trams arrive.
Trams can carry 20,000 passengers an hour - far more than buses - and some roads are expected to reach capacity for buses in as little as five years.
Trams will arrive at stops every five minutes and, because they run on electricity, there will be no fumes or on-street pollution.
Trams can move faster than buses because they have sensors which change traffic lights. They also have several doors, which means drivers do not have to wait long for queues of passengers to board.
The Caf trams have a cage installed on the front so that anyone who is hit by them will not be crushed underneath the vehicle.
Edinburgh trams in the past were prone to breaking down, which caused huge delays for passengers.
However, the modern trams will have shunt equipment so that if a tram in front breaks down, the rear tram can push it easily to the depot for repair.
When trams were installed in Dublin, the Irish capital saw a rise of between 20% and 35% in pedestrian footfall figures on Grafton Street, the city's main shopping thoroughfare, with some retailers reporting a 25% increase in trade.
But as a Tie spokesman said: "It's not about trying to sell the idea of trams to the people of Edinburgh any more because they are coming, they are here.
"Instead, we want to keep them best informed of the road closures and diversions and let them know when they will have a far better transport service which is clean, quick and regular."