Railway Tunnel, Islandarragh Road, Ballycastle, Co. Antrim

Railway Tunnel

This stone railway tunnel at Islandarragh Road, Ballycastle, was constructed between 1879 and 1880 as part of the Ballycastle Railway Company's narrow gauge line connecting Ballycastle and Ballymoney. The tunnel passes beneath a road and stream, measuring approximately 35 metres in length. It is constructed in stone with a barrel vault profile defined by a prominent ringstone arrangement at its elevation, which provides both structural stability and substantial loading gauge. The parapet remains intact and in good condition.

The tunnel was built under the direction of Belfast-based architect and engineer James Francis MacKinnon, with construction carried out by contractors Butler & Fry of Ballymena. The narrow gauge line (3 feet gauge) was approved by the Ballycastle Railway Act of July 1878, following a scheme that had first been proposed in the late 1850s and was revived in 1876 after earlier rejection by the House of Lords in 1868. The scheme was designed to avoid major earthworks and construction costs by following a curving route with only small bridges and two significant engineering features: a four-arch stone viaduct over the Glentow River south of Ballycastle and this tunnel at Cape Castle. The line opened in October 1880 and operated as a roughly 16-mile (26-kilometre) route between the two towns.

The tunnel has become largely integrated into the surrounding landscape, disguised by mature trees and vegetation along its upper level, which now functions as a roadway. A water stream flows across the span from above, and signs of flooding and water build-up are visible at the tunnel's centre.

Although initially well-used, the line proved unprofitable. It closed in March 1924 but reopened months later after being absorbed by the Northern Counties Committee. The entire network passed to the Government-owned Ulster Transport Authority in 1948-49, and the Ballycastle line was closed permanently in July 1950. Most associated structures have since been cleared, but this tunnel survives in its original form and structure. Many other buildings and features from the route, including the halt at Cape Castle itself, have been demolished. The tunnel remains an important part of the area's economic, cultural and social history and is of industrial archaeological interest. Recent proposals to restore the route as a greenway have been put forward, though the outcome remains uncertain.