Bridge No 12, Conywarren TL, to west of 14 Beltany Road, Omagh, Co Tyrone, BT78 5NA

Bridge No 12 at Conywarren, west of 14 Beltany Road in Omagh, County Tyrone, is a single-span concrete and steel rail-over-river bridge built around 1930. Aligned north-south, it previously carried the Londonderry & Enniskillen Railway over a narrow stream, positioned north of Gillygooly Road. The railway track has since been removed from the carriageway and surrounding areas.

The bridge is devoid of ornamentation or discernible style. Its square-headed superstructure features flanged and riveted wrought-iron parapets and a track-bed carriageway with semi-circular ends, supported on poured concrete abutments with smooth finish. A stringcourse runs below carriage level, topped with a concrete parapet and coping. It is an early twentieth-century iron and concrete railway bridge of modest proportions and is not considered a good example of its type, with other better bridges listed along this railway line.

A bridge on this site first appears on the second edition Ordnance Survey map of 1854. The current structure is a replacement dating to around 1930. The railway was initially captioned the Londonderry & Enniskillen Railway, later becoming the Great Northern Railway (Ireland) by the third edition map of 1905–6.

The Londonderry & Enniskillen Railway Company was incorporated in 1845, authorised to construct a single-track line extending southwards from Londonderry. Work began soon after, and by April 1847 the line had reached Strabane. Construction costs were relatively low at approximately £10,000 per mile. However, the first section struggled commercially due to its brevity, storm damage, and competition from the Strabane Canal and Foyle Navigation. The line only proved successful following construction to Omagh (1852), Fintona (1853), and Enniskillen (1854), bringing important commercial advantages to these towns and the agricultural lands along the Foyle valley and its tributaries. Omagh and Strabane became major market centres for goods conveyed northward to Londonderry port.

The Londonderry and Enniskillen Railway was leased to the Dundalk & Enniskillen Railway Company in 1860 (subsequently the Irish North Western Railway Company) for 99 years. The INWR was absorbed by the Northern Railway Company on 1 January 1876 and merged with the Ulster Railway Company on 1 April 1876 to form the Great Northern Railway Company (Ireland). Following post-war competition from road transport, the GNR ceased as an independent company in 1953, when the entire system was acquired jointly by the Governments of Northern Ireland and the Republic of Ireland. In 1958, the portion within Northern Ireland passed to the Ulster Transport Authority. A subsequent period of contraction saw many lines deemed unremunerative closed down.

The bridge is situated on grassy embankments in grassy surroundings on the outskirts of modern developments. It is recorded as derelict and is of industrial archaeological interest.