Empty trams running on Princes Street by January

Empty tram cars will be test-run for half-a-year before opening their doors to the public – without picking up a single passenger.

The deserted carriages will shuttle through the Capital as part of sweeping safety tests before the project is officially handed over to the city.

Transport chiefs claim thorough testing is “essential” to ensure the line is working correctly before launch, but today one tram expert said the six-month trial was “excessive”.

Professor Lewis Lesley, technical director of light rail company Trampower, insisted one month of testing was the “normal minimum” to debug new routes but said it can take longer “depending on the relationship between contractor and client”.

“It does seem an excessive amount of time given that it’s a simple end-to-end route. Nottingham is a more complex system and I think the final testing period for them was two months. A lot of European cities build tramways in six months.”

City leader Andrew Burns, below, said the authority faced a “PR challenge” to explain empty carriages to residents who have been waiting to see working trams on the streets since 2008.

“When roadworks are clear – and by the end of this year all the big construction will be clear – and trams will be tested all over the city, people will be saying ‘when can we get on here’,” he said.

Adequate testing of Edinburgh’s curtailed route is vital for tram driver training, working out kinks in the line and ensuring the route is running smoothly before commissioned for use.

Testing – or “shadow running” – has already taken place on the completed stretch from Gogarburn to Edinburgh Airport but 800 individual tests are needed to take place across the route.

Simon Johnston, editor of Tramways and Urban Transit magazine, said he “completely understands” why testing in Edinburgh could take up to six months and urged residents to be patient.

“The last thing you want to do, especially in Edinburgh, would be to rush it in and for it to close for an extended period. That puts even more bad publicity on a scheme which is not particularly well viewed.”

Transport convener Councillor Lesley Hinds said: “As was the case with successful testing between Gogar and the airport, we’ll make sure that residents and key stakeholders are aware of what’s involved to limit disruption, appropriate signage will be in place and we’ll make clear important safety information.”

The News has told how drivers were paid to steer trams around a test track to prevent the wheels from seizing up while they were in storage – costing around £500,000 in wages before the project goes live.

Transport Minister Keith Brown said: “This is positive and welcome news for residents and businesses and offers further assurance that good progress is being made in relation to the revised timetable.

“Since the new governance arrangements were put in place, Transport Scotland has played a key role in supporting the council and contractor in getting the project back on track.

“While contractors need to conduct in the region of 800 individual tests to fully test the entire system once the works are complete, if the current level of progress is maintained then we are confident of more good news when the project team reports back later this year.”