Strategic Route 6 - North London Line and Thameside was the designation Network Rail gave to a grouping of railway lines in Greater London and the East of England region that encompassed the London, Tilbury and Southend Line and overground commuter lines within London. The route provided key services to Southend and London suburban areas as well as supporting various freight routes within London.[1]
In 2010, Network Rail restructured its route categorisation. Route 6 was split into Strategic Route E: North London Line, and Strategic Route F: Thameside.[2]