Simplify the following text for a Grade 21 native English-speaking person.
Original: 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 obstructing the passage of Airport Express trains ) .
Simplified: 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 Mei Foo station ; Nam Cheong Station ( an interchange station on the Tung Chung Line , jointly operated by the MTRC and KCRC ) and 4-Tracking Works ( the additional two tracks , 4 km in length , allow the Tung Chung Line trains to stop at Nam Cheong without obstructing the passage of Airport Express trains ) .