Construction of the Ma On Shan line began on 12 February 2001 and it fully opened for service on 21 December 2004, 3 days earlier than the proposed opening date. KCRC estimated the construction costs to be HK$10 billion. Over a thousand passengers took the first train from Tai Wai on the first day of service. Since then, the usage of buses and taxis in the area decreased by as much as 50%. It was reported that some bus routes operated by KMB saw a decrease of ridership by one-third in just a few days.