When ive been on the 21/X21 that you may get just a few pensioners traveling through Peterlee bus station to Sunderland and vice versa, only problem is that the X21 is timed off Peterlee bus station after service 23 to Sunderland leaves, you may get a couple of passengers waiting for the X21. From Sunderland the X21 is timed out just after main service 22. Been a few times that fare paying passengers are boarding the X21 from Sunderland and traveling between Vilette road junction and ryhope as either service 60/61 not in the stands at Interchange when their are running late and leaving gaps in their stands. Why is it the buses on the 21/X21 when traveling on the A19 always having the heating blasted out (thought sometimes that my blood was going to boil out of my skin lol), unless something changes I cant see this lasting out a year for the X21. Don't know why Arriva cant change service 22 and run it as a X22 between Peterlee and Sunderland via X21 route and have service 23 running as a all stopper service via Dalton Park.