IT WILL involve looking out for unexploded bombs, potential archaeological traces and even the remains of Edinburgh's former tramway. Up to 125 workers will start digging up the capital's roads in earnest next month in the latest £60 million phase to return trams to the city in 2011 after a gap of 55 years.
A map of the planned Edinburgh tram network. Picture: TSPL
Before tram lines can link Newhaven with Edinburgh Airport via Princes Street, an intricate web of water pipes, gas mains and power and telecommunications cables will be moved from up to 5ft below the streets.
In an innovative move reminiscent of the Heineken television advertisement which portrayed a perfect world where utility companies all dig up the road at the same time, one firm, Alfred McAlpine, will do all the work rather than leaving it to the 16 utility companies involved.
Excavation got under way in Ocean Drive in Leith two weeks ago, with sections of Leith Walk and Roseburn to follow next month.
It will be restricted to 200yd sections being dug up at one time, with a maximum of one lane being shut in each direction rather than any complete road closures.
At the busiest junctions, temporary "Bailey bridges" may be installed to carry traffic over roadworks, such as at Haymarket, and on Princes Street at the Mound and Lothian Road.
Utility diversion work will cover a second section of tram line, between Roseburn and Granton, which it is hoped can also be completed by 2011 if money allows.
But the final section of a loop between Granton and Newhaven, and a western extension to Newbridge, have been shelved pending further funding being found.
Extensive radar surveys and trial digs will precede the utility work, but engineers acknowledge they may come across unexpected hazards.
These could include unexploded wartime bombs around Leith docks and at Gogar, on the edge of the airport, and archaeological relics near South Leith Parish Church in Constitution Street. There are also old tunnels under Leith Walk and near the Mound.
The work will be limited to 7am-7pm on weekdays and 7am-1pm on Saturdays. Some 40 per cent of the tram route is off road.
An extensive consultation programme has included 120,000 letters sent to businesses and residents.
TIE, the city council firm developing the £600 million trams scheme, has also issued a new tram map with several stops being renamed so they are not confused with electricity substations. The trams will generally run in the middle of roads, with buses and overtaking vehicles likely to be permitted to run over the tram lines.
Roundabouts on Leith Walk at Picardy Place and London Road are expected to be replaced with traffic lights.
