The Dalkey Atmospheric Railway (unofficial opening 19 August 1843, official opening 29 March 1844 – 12 April 1854) was an extension of the Dublin and Kingstown Railway (D&KR) to Atmospheric Road in Dalkey, Co. Dublin, Ireland. It used part of the Dalkey Quarry industrial tramway, which was earlier used for the construction of Kingstown (Dún Laoghaire) Harbour. It was the first commercial railway of its type in the world.