(11 Jul 2015, 6:40 pm)S813 FVK wrote Happens quite often. Has something to do with not wanting to leave them sitting spare in the depot all day i think. A resident of Sunderland may know more.
Yes - the gas buses are very fuel efficient compared to the ADL Enviro200s, so any spare gas buses (after meeting PVR of services 3/13/16/20) are allocated to service 4.
Still a rare/odd working nevertheless. Happens just as often as a red Merc on the Diamond services...