(07 Dec 2015, 6:46 pm)BusLoverMum wrote Only a tiny section of the route is an "express" service. The Peterlee-Darlington section is anything but and has already been ID'd as an "eco" route, like the 23.
If you were to renumber it you could maybe make the 21/21A/X21 MAX services I feel as there is a few bits in the route where there is a fair gap between bus stops although it isn't limited stop although neither is the X75/X76 and they are becoming MAX in the new year. Could probably easily change the brand from Eco to MAX.