Not quite the ordinary GWR HST service that it first appears to be. Rather than racing along the up main as is usual, 43197 is trundling slowly along the up relief line at Circourt Bridge, Denchworth, on 23 December 2015 with the 3Z83 09:56 Bristol St Philips Marsh to Paddington ECS. Quite why this was routed along the relief line is not clear, as despite being briefly checked by a red signal near the next roadbridge, nothing overtook it, and it rejoined the up main at Wantage Road.