Both lines are divided into 5 zones, the central zone being shared. Fares are calculated based on how many zones a journey is taken through. There is a stop on the border of each zone, which is considered to be in whichever zone is more beneficial to the traveller. It is necessary to walk between the two lines, most commonly between O'Connell Street-GPO (on the Green Line) and Abbey Street (on the Red Line). Alternatives include buses (the number 18 links Ranelagh to Kylemore, although these are not included on the ticket) and taxis.