47615 Castell Caerffili / Caerphilly Castle & 47623 Vulcan arrive at Oxford on 1 August 1986 with the 1F14 09:17 Paddington to Oxford Network SouthEast service, with presumably one of them under test. It was common practice for Old Oak Common to send a recently repaired loco in tandem with a backup on an early morning out and back trip to Oxford.