However a reply from Craig Munday led us to re-think and investigate further – Craig said. In response to the photo challenge, I think the photographer is a bit out geographically. I think the location is just west of St Austell between Gover viaduct & Burngullow, the road bridge being Tervanion Road.
This led us to think again, and indeed meantime John also had a re-think looking further east. The five of us all agree that the location is as Craig suggests, the locomotive would have been working hard, as the exhaust shows, as the line climbs almost continuously from St Austell to Burngullow. Another proof is that Gover viaduct has bricks below the parapet whereas Guildford does not. Well done Craig.