Sutton Loop Line

Sutton Loop Line
Sutton platform 2 looking towards West junction with the St Helier Line
Overview
Type	Heavy rail
System	National Rail
Status	Operational
Locale	Greater London South of England
Termini	Streatham Sutton
Stations	14
Services	2
Operation
Owner	Network Rail
Operator(s)	Thameslink Southern
Depot(s)	Bedford Cauldwell for Thameslink Selhurst for Southern
Rolling stock	Class 319 Class 377 Class 455 Class 700
Technical
Number of tracks	2 1 bi-directional line at Wimbledon
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Operating speed	Maximum 60 mph

The Sutton Loop Line, also known as the Wimbledon Loop, is part of Thameslink and is the circular route formed where the St Helier line diverges from the Portsmouth Line at Streatham South junction and rejoins it near Sutton station. The Sutton Loop includes the historic Surrey Iron Railway stations of Hackbridge/Carshalton, which was the first Iron Railway in the world, following the course of the river Wandle to the Thames. 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", 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.

In a clockwise direction round the loop, the stations are:

Traction current is supplied at 750 volts DC via the Third Rail. The supply for this is overseen by Selhurst Electrical Control Room. Signalling is Track Circuit Block with multiple aspect colour light signals, controlled by Victoria Southern Power Signal Box. The line is double track throughout, except where a short bi-directionally signalled single line section passes through Wimbledon station platform 9. Originally the Down St Helier Line used platform 10 at Wimbledon, but this is now used for the Croydon Tramlink terminus which currently comprises a single platform at the southern end, split into two sections so two trams can be held at the same time.ref>https://www.tfl.gov.uk/travel-information/improvements-and-projects/wimbledon-to-croydon-tram-link</ref>

Thameslink runs services from Luton and St Albans, via Blackfriars round the loop. Clockwise services are described as "Sutton via Mitcham Junction" and anti-clockwise as "Sutton via Wimbledon". Additionally during service disruption or when the core section of the Thameslink route is closed, Thameslink Sutton Loop services start and end at London Bridge low level station.