The Harpenden to Hemel Hempstead branch railway, or the Nickey Line as it is generally known, was a seven-mile-long railway built in 1877 to connect the villages between the West Coast Main Line, which ran north to Birmingham and Manchester, and the Midland Main Line, which ran north to Leicester and Sheffield. The etymology surrounding the term “Nickey Line” is obscure, and there are many competing theories as to how the name originated. The line was initially used mostly by freight trains, but passenger services were also started, and the line eventually connected several stations in Harpenden, Redbourn, and the growing suburbs of Hemel Hempstead.

During its time in service, the Nickey Line was used by commuters traveling into London, and also cargo trains that ferried the straw plait produced in Hemel Hempstead up to the hat factories of Luton. The railway line was also used by the experimental “Ro-Railer,” an unusual vehicle that could be used on both road and rail, but this was ended in the 1930s after only occasional use.

The line was never used intensively, and the last passenger train between Harpenden and Hemel Hempstead ran on the June 16, 1947, though freight traffic continued until 1979. Following this, the line was closed, and the rails were removed. The line was then converted to a multiuse cycle- and footpath, and is now popular with bicyclists, walkers, dog-walkers, and budding marathon runners.

Visible remains of the railway can be seen all along the line, but the most extraordinary sights is up toward the Harpenden end of the line, and includes the extant platform and signaling post at Roundwood Halt (about a mile down from Harpenden station), as well as the enormous brick railway arches by the Highfield Oval. Also of interest are the woods on either side, which are excellent places to see the stunning bluebells that emerge in English woods in springtime.