(05 Aug 2014, 5:31 pm)Tom wrote Just thinking - if there are additional peak time runs on the X21, could the service be operated by Citaros?
Not really - refer to the second last quote on this post.
As GuyParkRoyal said above, there are a lot of times where service X21 has a lot of customers. Much like the present situation with service 685, this is Go North East hammering another nail into Arriva's coffin.
We've recently discussed Stagecoach on Teesside's operations in regards to double deckers, and I must say that Go North East is very good at investing into double deckers if the service justifies them at peak times - maybe they don't care about all those pennies after all, and do care about their customers!