On a Bournemouth-Sheffield train. The tablet apparatus is extended.

Peter Kerslake says "73087 approaches Corfe Mullen Junction as the line forming the large triangle joining the LSWR main line in the northbound direction can be seen diverging above the second coach. The short stretch of single line which it is just about to leave runs down from Corfe Mullen southwards just a mile or so to Broadstone and the LSWR main line.
The first Standard Class Fives came to the Somerset and Dorset in May 1954 with 73051 and 73052.
73050 joined them the following month straight from being exhibited at the International Railway Congress Exhibition held at Willesden."

A bit of clarification/correction on Peter Kerslake's comments. We are looking eastwards. The train is indeed approaching Corfe Mullen Junction from Broadstone Junction, using the Wimborne Cut-Off, and about to pass under Br.223, 'Corfe Mullen Junction Bridge', or before the junction came into being in 1905, 'Blandford Road Bridge'. From 1885 until 1905, the two bi-directional single lines from Wimborne Junction (left) and Broadstone Junction (right) ran parallel from here to Bailey Gate Station before making any physical junction. The train has past Corfe Mullen Halt, which was about one mile in rear.