The route follows the length of the Kāpiti Coast north of Wellington, running from the city through Porirua and along a narrow coastal corridor between the Tasman Sea and steep escarpments, with wide views of the coastline, wetlands, and distant ranges along the way. Originally built in the 1880s by the Wellington and Manawatū Railway Company and later absorbed into the national network in 1908, the line formed a crucial link between Wellington and the lower North Island. It was progressively upgraded over time, with double tracking and realignments improving capacity, and electrified to Waikanae on 20 February 2011. Today, the line remains a vital commuter and regional corridor, connecting rapidly growing coastal communities such as Paraparaumu and Waikanae with the capital, while providing access to beaches, nature reserves, and popular walking and cycling tracks throughout the journey.