The new EMU trains, which are the most advanced AC train in the world for the 21st century, consist of twelve(12) cars units for the existing East Rail, seven(7) cars units for the West Rail (to start operation in 2003), and four (4) cars units for the new Ma On Shan line. These cars employ three design concept, "Frequent Passenger Service", "Friendly to the Environment" and "Low Life Cycle Cost".