The dummy runs, which are being deployed 18 months before the trams even hit the streets, are designed to prevent wheels from seizing up while in storage – costing around £500,000 in wages before the project goes live.
Experts today confirmed that 18 trams already delivered to the Capital would have to be driven regularly along a 470-metre track at the Gogar depot to safeguard against defects that can appear when the high-tech vehicles remain stationary for too long.
Within six months a dozen tram drivers will have been hired to regularly “run” the trams, with four drivers already recruited.
The tram operators will also test control systems, including voice communications, signalling and power management.
A source close to the tram drivers said: “The drivers are going to be paid to work Monday to Friday at Gogarburn moving the trams around the depot to stop them seizing up. It’s just ridiculous after all that’s happened with this project.”
Lothian Buses, which is recruiting drivers and will eventually operate the trams, was unable to comment.
Insiders have confirmed part of drivers’ duties will include “managing tram movements”.
Professor Lewis Lesley, technical director of light rail company Trampower, said railway vehicles had to be moved at least once a week to prevent damage to the wheels and roller bearings.
“When a railway wheel is left unmoved for a while it develops a flat which is not like a flat car tyre because it’s a permanent flat on the corner of the wheel,” he said.
“If there are 16 wheels on each Edinburgh tram that will mean a lot of money. The flat can be just a fraction of a millimetre but it’s enough to damage the wheel when it rotates and it’s a hammer blow every time it hits the track, which it can also damage.”
Mr Lesley, who was once behind a £35 million plan to run trams around north Edinburgh, added: “It’s essential the trams are kept turning. At least once a week you’ll need to take it for a full run in order to ensure you don’t have that problem.”
Simon Johnston, editor of Tramways and Urban Transit magazine, said: “The trams will require a certain amount of running in. You might only require two or three hours a day running it up and down a track.”
Councillor Steve Cardownie, a past detractor of the project, said: “Lothian Transport has assured us that the recruitment of the drivers is crucial to the operation of the trams. They run a very efficient and award-winning bus fleet and having that expertise, I would be surprised if they were doing anything regarding the trams that they should not be doing.”
But long-standing tram critic, engineer John Carson, said: “We are now into job creation. Instead of having five or so tram drivers we are now going to have more than that to keep them all running.”
Conservative Lothians MSP Gavin Brown added: “Given the shocking value that the tax payer has had so far I would look to the council to give the public a full justification as to why drivers are needed now.”