David J. Hayes says " Although I might be wrong, the hoppers look loaded, so I'm going to hazard a guess that this train has traversed the West London Line to reach Southern Region metals. If I'm correct, then this could be 6O66 (KH), the 11:25 SSuX Acton Yard to Chessington coal turn, which was booked through Clapham Junction at around midday (the service was later amended to depart Acton at the slightly earlier time of 11:18). There was also an early evening 6O81 (KH)departure from Acton at 18:15 SSuX to Wimbledon. Such workings during the 1970s sometimes had a brake tender or two behind the loco and were often staged at Wimbledon before going forward to the coal depots at Chessington and Tolworth"