(08 Mar 2015, 8:07 pm)Kuyoyo wrote No, Go North East and United used to share what is now the X12/X2 (back when it was the X1) and also shared the X10. Then they split with United/Arriva retaining the X1 and GNE the X10.
There is next-to-no potential for competition on the Durham to Middlesbrough route as the bulk of the route has a large level of service already (Durham-Coxhoe is every 10 minutes with Arriva on 56/57/57a/X12 plus the hourly 58, Sedgefield-Middlesbrough has the X12 every 30 and the 21a every hour, along Durham Road in Stockton you have those 2 plus Stagecoach's 58 every 12 minutes and the Stillington service every hour - presently with Leven Valley).
It's the old Tyne Valley question though isn't it. You'd have thought there was next to no potential there, until GNE stuck their size 12s in with the X84/X85. Similarly, the risk of competition between Bishop and Darlington, caused Arriva to get their act together with the X1.
I'd say the A177 corridor has the same potential. Arriva would sharp up their game at the slightest smell of competition. They know that there are capacity issues (emails from depot confirm that), but it's never not going to be a careful balance between supply and demand.