The Lok Ma Chau Spur Line is the second railway link between Hong Kong and Mainland China, relieving passenger congestion at Lo Wu Station. The 7.4 km (4.6 mi) alignment branches off the existing MTR East Rail Line north of Sheung Shui Station and then runs to the Lok Ma Chau Station where customs and immigration facilities are provided. The terminus is connected to new Futian Checkpoint Station (formerly named as Huanggang Station) of the Shenzhen Metro Line 4 by a pedestrian bridge across the Shenzhen River.
The KCRC has adopted a combined tunnel and viaduct scheme for the spur line. From Sheung Shui to Chau Tau, the railway runs through tunnels, the railway then runs on viaducts until it reaches Lok Ma Chau Station.
The Spur Line project comprises four major sections, namely, the tunnels, the viaducts, Lok Ma Chau Station, and the modification works at the existing Sheung Shui Station. Unlike the rest of the East Rail Line, which is above ground, this section is located underground.
The Government of the Hong Kong Special Administrative Region endorsed the Corporation's construction of the Lok Ma Chau Spur Line on 14 June 2002. Construction commenced in January 2003. The line was officially opened on August 15, 2007, in ceremonies led by Henry Tang, the Chief Secretary for Administration of Hong Kong.