Northern Railway of Ireland was an Irish gauge 5 ft 3 in (1,600 mm) railway company in Ireland.
It was formed by a merger of the Dublin and Drogheda Railway (D&D) with the Dublin and the Belfast Junction Railway (D&BJct) in 1875. In 1876 it merged with the Irish North Western Railway (INW) and Ulster Railway to form the Great Northern Railway (Ireland).
References
Northern Railway of Ireland Wikipedia(Text) CC BY-SA