𝐓𝐡𝐚𝐦𝐞𝐬𝐥𝐢𝐧𝐤

Thameslink is a 24-hour main-line route in the British railway system, running from Bedford, Luton, St Albans City, Peterborough, Welwyn Garden City, London Blackfriars and Cambridge via central London to Sutton, Orpington, Sevenoaks, Rainham, Horsham, Three Bridges, Brighton and East Grinstead. The network opened as a through service in 1988, with severe overcrowding by 1998, carrying more than 28,000 passengers in the morning peak. All the services are currently operated by Govia Thameslink Railway.

The Thameslink Programme was a major £5.5 billion scheme to increase capacity on the central London section by accommodating more frequent and longer trains, and providing additional routes and destinations. The new services began operating in 2018. In 2016, new Class 700 trains started operating on the route and replaced the Class 319, Class 377 and Class 387 trains which were withdrawn and transferred elsewhere.

Route

Much of the original route is over the Brighton Main Line (via London Bridge) and the southern part of the Midland Main Line, plus a suburban true loop (circuit) serving Sutton. A branch via the Catford Loop Line to Sevenoaks was added in 2012. Sections to Peterborough on the East Coast Main Line, Cambridge via the Cambridge Line, Horsham on the Arun Valley line and Rainham via Greenwich were added in 2018. East Grinstead is also served during peak hours.

The route through central London (today known as Thameslink core) is via St Pancras International for connections to Eurostar and the East Midlands; Farringdon, for London Underground Circle, Metropolitan and Hammersmith & City lines, and the Elizabeth line; City Thameslink, which replaced the demolished Holborn Viaduct station and has a southern entrance serving Ludgate Circus; Blackfriars, for main-line rail services and the Underground District and Circle lines; and London Bridge for main-line links into Kent and Sussex and the Underground Northern and Jubilee lines. King's Cross Thameslink on Pentonville Road closed on 8 December 2007.

Trains operating the "main line" service (Bedford and Cambridge to Brighton, Peterborough to Horsham) include first-class accommodation; those operating from Luton, St Albans and Kentish Town to Sutton, Sevenoaks and Orpington are usually standard class only. When Govia operated the original Thameslink franchise these services were designated "Thameslink CityFlier" and "Thameslink CityMetro" respectively, but First Capital Connect dropped this branding. Govia Thameslink Railway now refers to these services as Route TL1 (formerly Route 6) and Route TL2/TL3 (formerly Route 7/8) respectively.