Railway Tunnel, On Belfast-Larne railway line, White Head, Carrickfergus, Co Antrim, BT38

Railway Tunnel on the Belfast-Larne line at White Head, Carrickfergus, County Antrim

This tunnel carries a curved single-track railway line along the foot of a basaltic headland at White Head. It measures approximately 4.75 metres wide (15 feet 6 inches) by 191 metres (209 yards) long.

The tunnel was constructed by the Carrickfergus & Larne Railway Company and opened in October 1862. The single-track line was worked by the Belfast & Northern Counties Railway Company. In 1903, the Belfast & Northern Counties Railway was acquired by the Midland Railway and operated through its Northern Counties Committee. The Midland became part of the London, Midland & Scottish Railway in 1923.

The northeast entrance has a parabolic profile and is embellished with rusticated limestone blocks which contrast with its black random rubble spandrel facing the cliff end. A metal sign reads "Whitehead Tunnel; Distance 191m. Refuges at 20m intervals on both sides".

At the southwest end, the first 20 metres of the tunnel is a 1920s extension. The original random rubble side walls with limestone quoins survive, but the original arch has been replaced with sloping pre-cast reinforced-concrete roof slabs set on mass concrete extensions to the wall heads. This concrete dates from the 1990s and replaced spalled concrete from the later 1920s. The original parabolic tunnel profile is visible beyond, with quoins and arch ring both of brick. A metal sign at this end reads "Whitehead Tunnel". The defunct single-track line survives inside and at both ends of the tunnel.

Between 1926 and 1929, the London, Midland & Scottish Railway doubled the line between Carrickfergus and Whitehead. The 'down' line to Whitehead continued to use the tunnel, while the new 'up' line to Carrickfergus was directed along a cutting blasted through the rocky headland on the seaward side of the tunnel. A short extension to the southwest end of the tunnel was also constructed at the same time to eliminate the risk of rockfalls where the line approached the original tunnel entrance. The extension in concrete during the 1920s illustrates the evolution in technology from a brick arch to reinforced-concrete beam.

A short distance beyond the north end of the tunnel, the track is carried over a re-entrant on a three-arch masonry viaduct. The operational two-way line lies on the seaward side of the tunnel and runs through a deep rock cutting. It is protected from rock falls at its south end by a gabioned rubble masonry wall.

In 1994, a rock fall forced the abandonment of this section of the down line at the tunnel and the re-ballasting of the up line around the headland for two-way working. Despite work to stabilise the cliff face above the tunnel, there are no immediate plans to reopen it, although this remains a long-term objective should finances permit.

The tunnel is one of only a few in the Province, the others being at Downhill, County Londonderry (opened 1853; 307 yards long) and Lissummon, County Armagh (1864; 365 yards long). Historically, it was one of the most significant engineering works on the Carrickfergus-Larne line, which was an important national link for the cross-channel ferry to Scotland. Its spectacular setting at the bottom of the cliff at White Head clearly illustrates why it was built. Its juxtaposition to the three-arch viaduct to its north and the 1929 'up' line through the rock cutting to its east both enhance its interest.