David J. Hayes says" The West London Line was traversed by numerous block tanker trains during the 1970s, many originating from the various refineries/storage tank farms situated both north and south of the Thames estuary. I assumed this was such a loaded working from one of the Grain area refineries, which would've normally recessed at Hoo Junction. However, based on WTT information and the two-character headcode display of what appears to read "F1", this may well be 6E63, the 13:10 Brighton to Temple Mills (empties from various terminals/fuelling points?), which was booked through Kensington Olympia at 4:28pm. I could well be wrong, though".