Peter Kerslake says "Bristol Bath Road's 5048 Earl of Devon makes heavy weather of the climb to Hemerdon summit with the Sunday West to North express which it will work back home to Bristol.
The steam heating seems to be working further down the train but 5048 is losing a lot of steam and the load of seven coaches plus a "Siphon " is the maximum load for an unassisted "Castle" over the banks to Newton Abbot. The "Siphon" may well be an Enparts van with locomotive parts for repair at Swindon, and in that case would come off the train at Bristol.
There has clearly been substantial track renewal recently and I have taken this photograph from the overbridge at the summit. It's still possible to obtain some decent images from this very location, but it is dreadfully overgrown now