The 1.2-kilometre (0.75 mi) tunnel was built between 1847 and 1855 and runs from Blackpool to Kent Station on the Lower Glanmire Road.

It is the longest operational rail tunnel in Ireland,[2] and is included on the Record of Protected Structures maintained by Cork City Council.

[3] The tunnel was designed by architect John Benjamin Macneill for Great Southern and Western Railway (GSWR) and built by contractor William Dargan.

A few days later, the chairman, some directors, a secretary, and an engineer of GSWR walked the full length of the tunnel.

[5] A commemorative plaque to the two men, Michael Driscoll (24) and John McDonnell (30), was dedicated where the modern road bridge passes over the northern mouth of the tunnel at The Glen.