(23 May 2013, 3:24 pm)Andreos1 wrote Airshow? Great North Run? Festival of the North? Mouth of the Tyne Festival? Some sort of Summer Service?
Id assume any contracts for events would specify low floor vehicles, so this could be covering commercial work on those weekends... Just a guess.

Airshow buses are normally pooled from Sunderland's spare fleet and the Teesside school fleet, hence in previous years the Olympians were used on the 510 (presumably depending how many have arrived by then, this year's Teesside vehicles will be Tridents). The Great North Run only happens on a Sunday so there's enough spare buses to cover the speical workings. Stagecoach don't get involved with the Mouth of The Tyne Festival as far as I'm aware.