Dublin and Drogheda Railway
Dublin and Drogheda Railway (D&D) was a railway company in Ireland which publicly opened its 31¾ mile main line between Dublin and Drogheda in May 1844. It was the third railway company in Ireland to operate passenger trains and the first to use the Irish standard 5 ft 3 in (1,600 mm) gauge.
Source: Wikipedia — Dublin and Drogheda Railway (CC BY-SA 4.0)