The London, Tilbury and Southend line, also known as Essex Thameside, is a commuter railway line on the British railway system. It connects Fenchurch Street station, in central London, with destinations in east London and Essex, including Barking, Upminster, Basildon, Grays, Tilbury, Southend and Shoeburyness.

Fenchurch Street railway station, also known as London Fenchurch Street, is a central London railway terminus in the southeastern corner of the City of London. It takes its name from its proximity to Fenchurch Street, a key thoroughfare in the City. The station and all trains are operated by c2c. Services run on lines built by the London and Blackwall Railway (L&BR) and the London, Tilbury and Southend Railway (LTSR) are to destinations in east London and south Essex, including Upminster, Grays, Basildon, Southend and Shoeburyness.