Detailed MTR data were provided by the Hong Kong MTR Corporation . The data , from 1 January to 31 March 2020 , included masked card/ ticket ID ( the ID after masked and processed , not the original ID on cards ) , entry / exit station , entry / exit time , ticket type ( smartcard / ticket ) and card type of each passenger . The MTR system has five card types : adult , child ( ages 3 - 11 years ) , student ( ages 12 - 25 years and enrolled in a primary / middle / high school , university or institution of higher education ) , senior ( ages 65 years and above ) and others ( e.g. , disabled , MTR staff ) . The MTR data excluded airport express lines and the light rail systems .