[2] The bridge and tunnel were built by the Great Southern and Western Railway (GSWR) company to connect Kingsbridge station to the Dublin docklands.

Before the line was built the Midland & Great Western Railway (MGWR) company had built a railway along the Royal Canal which enabled them to transport goods directly from Spencer Dock to Broadstone station where MGWR was based.

An exception to this was occasional match-day services carrying Gaelic Athletic Association fans from southern lines to Connolly Station for Croke Park stadium.

[3] However, from the early 21st century, rail transport planners and interest groups such as Platform 11 debated the use of the bridge and tunnel to link the operationally separate passenger lines which then terminated at Heuston and Connolly stations.

[4] Ultimately, in November 2016, the bridge and tunnel were reopened to more regular passenger traffic.