A rail link to Melbourne Airport has been proposed in multiple forms at various times in the history of the airport. Most such proposals have been for a heavy rail line between Melbourne Airport at Tullamarine and the Melbourne CBD, often as an integrated component of the Melbourne rail network. Some plans, however, have utilised alternative forms of mass transit or suggested a segregated and dedicated public transport link to the airport. Relieving traffic congestion and creating better access to the airport are frequently cited as reasons for the development of the link. Businesses that would be negatively impacted by an airport rail link include Transurban, whose CityLink toll revenue would be affected, and Melbourne Airport, whose revenue from car parking would be reduced.