Despite its name the line does not run along the top of the North Downs, but loosely shadows the main chalk ridge of the North Downs between Redhill and Ash at a lower level. Between Reigate and Gomshall the line runs along the foot of the North Downs escarpment in the Vale of Holmesdale. At Guildford it runs through the gap in the Downs carved by the river Wey, with a short tunnel just south of Guildford station, and further west between Guildford and Ash the line runs to the north of the Hog's Back. It then follows the Blackwater valley as far as Sandhurst, before continuing to Reading.
History of the line's construction
The line was authorised by Acts of Parliament in 1846 and 1847 and most of it was constructed by the Reading, Guildford and Reigate Railway Company (RG&RRC), opening in 1849. (A central section of the line near Guildford was built by a predecessor of the LSWR.) The stated objective of the company was to <blockquote>"secure through traffic passing between the West, North and Midlands and the Channel Ports avoiding the congestion of London and thus saving time, distance and expense."<ref... Read More