While the construction of the Tung Chung Line was still underway, the plan to build a railway corridor serving the northwestern New Territories was conceived. Space had been reserved for the addition of an interchange station and two extra tracks (to allow nonstop service for the Airport Express) between Olympic and Lai King. Originally known as the Airport Railway Phase 2, the contracts of the West Rail Line Interface Works were awarded shortly after construction works of the West Rail commenced. The project comprised Mei Foo Interchange (modification of the existing Mei Foo station on the Tsuen Wan Line to provide a pedestrian link to the West Rail Line Mei Foo Station); Nam Cheong Station (an interchange station on the Tung Chung Line, jointly operated by the MTRCL and KCRC) and quadruplication works (the additional two tracks, four kilometres in length, allow the Tung Chung Line trains to stop at Nam Cheong without blocking the passage of Airport Express trains).