London walks - Sutton to Wimbledon - the Thameslink loop

The Sutton Loop Line,[1] also known as the Wimbledon Loop,[2] is a railway line that diverges from the Portsmouth Line[1] at Streatham South junction and rejoins it near Sutton station. Trains leave southwards from Streatham to enter the loop and then return going northwards. The short section between West Sutton station and West junction is known as the "Wall of Death",[3] possibly due to the very steep concrete walls to the cutting on both sides and the sharpness of the curve which resemble the motorcycle ride at a funfair.