;Current service patterns
Southern is the main operator of passenger services and stations on the line east of
Portsmouth. Service patterns have varied over the years, but have always included a slow service (calling at most or all stations) from
Brighton to
Portsmouth. Regular services run from
London Victoria via Gatwick which avoid Brighton by using the tunnel between
Preston Park and Hove. These services run to Littlehampton (2016); similar services extended to Chichester, Portsmouth and Southampton particularly in the initial decades of open competition between operators, making use of statutory and negotiated
running rights. Other services run from London Victoria via Gatwick and the
Arun Valley line to
Bognor Regis or along more of the West Coastway line, between Ford and nearby Chichester, to Portsmouth or Southampton. All of the Southern services are operated by electric
multiple-units. Many of these trains join/"couple" or divide/"uncouple" during their journey, historically at
Barnham, today at
Horsham (except on Sundays, when trains still divide at Barnham). The section west of Portsmouth sees trains from typically three operators. Its stations are managed by
South Western Railway, who operate regular services from Portsmouth either to Southampton or to London Waterloo (less directly than its
Portsmouth Direct Line, instead via Fareham, Botley, Hedge End and Eastleigh).
Great Western Railway operate diesel passenger trains from Portsmouth to and , with occasional services to the West Country or . Southern operate hourly services: between
Brighton and
Southampton Central; and between
London Victoria and
Southampton. The Southampton to London Victoria trains introduced at electrification created many direct routes, from Southampton, Swanwick, Fareham and Cosham to the West Sussex coast and particularly to Gatwick Airport. In 2024, Southern proposed significant service pattern changes, by diverting all the services from Southampton Central to London Victoria to Portsmouth Harbour, as well as doubling Southampton Central to Brighton services, with an additional stop at
Woolston. The lightly-used Littlehampton to Portsmouth & Southsea and Bognor Regis services will be replaced by a new Brighton to Chichester (via Littlehampton) service. The new changes commenced in June 2024. ;Historic service patterns Beyond the line and its main links to London, before late 2007 trains ran from Reading or Basingstoke to Portsmouth or Brighton; Basingstoke to Portsmouth being current. The
Department for Transport withdrew the obligation of
South West Trains to run Brighton services — being somewhat orbital around
London — which left free train paths which were filled by extra Southern trains mainly bound to or from London. Prior to the 1980s electrification of the "(south) Hampshire lines", including the part of this line west of Farlington, they were operated as a separate entity terminating at Portsmouth – few trains traversed the Cosham to Farlington triangle which lies north of Portsmouth and Langstone Harbours, except a daily Brighton-to-Exeter through (direct) train. After dieselisation using
3H units in 1958, the general service pattern every hour was one semi-fast from Portsmouth to Southampton and Salisbury (some extended to Bristol), one stopping to Southampton Central and one train to Botley and Eastleigh (some extended to Reading and, until 1966, Romsey via Chandler's Ford). ==History==