Arun Valley line

A single track branch line was opened on 14 February 1848, with passing places at the intermediate stations at Crawley and Faygate. The line was doubled throughout in 1862. The stations now at Ifield and Littlehaven were not opened with the line, both being opened on 1 June 1907: Ifield as Lyons Crossing Halt and Littlehaven as Rusper Road Halt; both serving the outskirts of their nearby towns. An additional stop was opened at Roffey Road Halt', however this station was closed in the 1937, as the land next to the station had remained undeveloped.

Horsham railway station

The Midhurst Railways line from Horsham to Pulborough, Petworth and Midhurst was opened on 10 October 1859. The section from Hardham Junction to Midhurst was closed between 1964 and 1966. The Steyning Line from Horsham to Shoreham by Sea was opened on 1 July 1861 branching off at Itchingfield Junction south of Horsham. It closed in 1966.

The line between Hardham Junction south of Pulborough, and Arundel Junction on the coast line via Arundel was finally opened on 3 August 1863 creating a through route to Portsmouth.

Originally, the main LB&SCR route from London to Portsmouth used the Portsmouth line to reach Horsham. However, with the increase in demand at Gatwick Airport, the mainline services were re-routed in 1978 to serve the airport and then travel via Three Bridges.

The line was electrified using the (750 V DC third rail) system by the Southern Railway in 1938 as part of the proposals to electrify the lines from London to Portsmouth. This originally only covered the section from Horsham to Littlehampton and Barnham, as the main line was the line through Dorking and Sutton, as opposed to the line to Three Bridges, but plans were extended to electrify the "branch" as well in the same year.

Electric services were provided by electric multiple units. For most of the rest of the twentieth century, an hourly express service was provided which joined/divided at Barnham, with 4 or 8 coaches continuing to Bognor and 4 to Portsmouth Harbour. This called at Arundel, Pulborough and latterly Billingshurst, going via Sutton and Dorking.[3] An all-stations stopping service also ran hourly via Crawley to Bognor Regis, usually via Littlehampton.

Two bridges on the line, The Black Rabbit Bridge (just north of Arundel) and the Peppering Bridge (a few hundred yards further on) were replaced during the August Bank Holiday weekend of 2009. The line was completely closed to traffic during these major engineering works and a replacement bus service served stations between Arundel and Pulborough. As the two-week Arundel Festival was drawing to a close over the weekend, Southern maintained a service into the station from the West Coastway Line from Bognor Regis via Barnham and Ford, and a reversal at Littlehampton.[4]

• Butt, R.V.J. (1986). The Caterham Railway. Patrick Stephens Ltd. ISBN 1-85260-508-1. Archived from the original on 17 July 2011.