The Sussex route, which includes the Brighton Main Line and its branch lines, is among the busiest and most congested in the country, carrying 3,200 trains every weekday.
It’s critical to the regional and national economy, transporting high volumes of travellers from the south coast to the capital, as well as Gatwick Airport, the country’s second busiest international airport and a key gateway to the United Kingdom.
Our lead train operators are; Govia Thameslink Railway Ltd (GTR) who operate; Southern, Thameslink, Gatwick Express and Great Northern services and Arriva Rail London who operate London Overground.

Sussex Upgrades
We’re continuing to invest heavily in what is some of the oldest and most intensively used infrastructure in the country, spending more than £750m between 2019 and 2024 to improve track, signalling, structures, earthworks and stations as part of our Sussex Upgrades programme.
Key investments include the Arun Valley Improvement Project which has seen £22m invested over summer 2021 to improve track and signalling, stabilise earthworks and refurbish stations and structures on the lines from Arundel to Crawley and from Horsham to Dorking.
We have completed work to improve reliability at the southern end of the Brighton Main Line, between Three Bridges, Brighton and Lewes, will continue over 9-days and several weekends in early 2022. We’ll use the time to deliver over £15m of investment to improve reliability for passengers.
The signalling and track, at key junctions, on the lines into London Victoria is being replaced as part of the four-year Victoria Resignalling programme
Gatwick Airport station is being rebuilt with double the space for passengers. The investment will improve accessibility for all passengers, support a more reliable train service and provide a gateway station that befits the country’s second busiest airport.
But that’s not all. We’re investing in smaller but equally important upgrade projects right across the route. Find out more on the Sussex Upgrade Plan page.