Phoenix Park Tunnel is not used for regular passenger trains but sometimes opened for major Gaelic Athletic Association fixtures, it allowed regular passenger traffic in November of 2016.
Historically the line had not been used for regular passenger trains, with most traffic through the tunnel being freight or carriages and engines shunted between Connolly and Heuston for maintenance. It had occasionally been used for special passenger services, including traffic for major Gaelic Athletic Association fixtures. It reopened on 21 November 2016 for regular passenger traffic. 
