Córas Iompair Éireann

Córas Iompair Éireann (CIÉ) was formed as a private company by the Transport Act 1944 and incorporated the Great Southern Railways Company and Dublin United Transport Company, adopting the logo of the latter company, the so-called "flying snail". Great Southern Railways (GSR) was incorporated in 1925, having been Great Southern Railway since 1924. Essentially the GSR became – especially as it started to broaden its business interests into road transport – a monopoly transport operator. The Transport Act 1950 amalgamated CIÉ and the Grand Canal Company and formally nationalised CIÉ, changing its structure from that of a private limited company to a corporation under a board appointed by the Minister for Transport. The Great Northern Railway Act 1958 and the Transport Act (Northern Ireland) 1958 (c. 15 (N.I.)), passed by the Parliament of Northern Ireland, transferred the lines of the Great Northern Railway Board in the Republic of Ireland (including County Donegal) to CIÉ.

Until 1986, CIÉ operated as a single legal entity, although it was internally organised into rail services and two bus divisions – Dublin City Services and Provincial Services. The vast majority of services were branded CIÉ, although long-distance provincial buses were branded "Expressway" and Dublin electric trains DART. In 1987, CIÉ was reorganised into a holding company and three operating companies. In 1990, it sold its nine Great Southern Hotels, including its hotel in Derry, to Aer Rianta, the airports authority.

The company does not run any services on Christmas Day.

Since the enactment of the Transport (Re-organisation of Córas Iompair Éireann) Act, 1986, CIÉ has been the holding company for Bus Éireann, Dublin Bus and Iarnród Éireann/Irish Rail, the three largest internal transport companies in Ireland. It was originally to have operated the Luas tram system in Dublin, but that project was transferred to the newly created Railway Procurement Agency (RPA).

CIÉ's services are provided through three operating companies:

Dublin Bus, which provides bus services in the Greater Dublin Area, including most bus services within Dublin city and the County Dublin;

Bus Éireann, which provides intercity and regional bus services outside Dublin city and county and from Dublin to the rest of Ireland, as well as operating the city buses in Cork, Limerick, Waterford, and Galway and a number of other small urban bus systems;