In 1834 the first railway in Ireland was opened, running between Dublin and Dunleary . this heralded the beginning of the steam age in Ireland. In 1845 there were fewer than 100 miles of track, by 1855 there were 1,000 by 1865 this had doubled to 2,000. The area west of the Shannon too poor to offer profit to the railway companies was not well covered.

The railways encouraged people to travel, previously coaches may have traveled at speeds of up to 10 MPH canal boats 2 or 3, with trains reaching 20 MPH and fares set at half of that of the competition, the railways rapidly became the in way to travel and send freight, which could be dispatched to almost any destination in the country both efficiently and economically, encouraging Irish businesses to look further afield when selling their products.

Railway companies were early to realize Irelands tourist potential, they established hotels in seaside towns, such as Newcastle in County Down, and helped to develop other towns by publishing guide books. When bank holidays were introduced in the latter years of the 1800's poorer people were encouraged to travel to the seaside on special excursion trains.

The success of the railways was the precursor to the slow demise of the Irish canal industry which came into existence in 1731, by the mid 1850's there were 1,450 km (900 Miles) of navigable waterways in Ireland. The canals found it impossible to compete with the speed of the railways, for example in 1845 a load of coal took five days to go from Dublin to Galway by road and canal, by 1855 the same load would have went in ten hours. In 1845 the Royal Canal was sold to The Midland and Great Western Railway Company, who built a line along the canal banks.
See Canals in Ireland.

The railways had a significant impact on Irish Industry, enabling raw materials and finished goods to be transported more efficiently, although businesses located in or near ports were at a distinct advantage. Brewing is perhaps a good example, in 1837 there were 247 breweries in Ireland by 1901 this had fallen to 41, most of these were located near the coast, of these Guinness was by far the largest, producing three quarters of the beer brewed in the country. Other industries were encouraged to set up businesses and take advantage of the rail system, one such was Pattersons Spade Mill at Templepatrick County Antrim, which distributed its products not only across Ireland but to the British mainland also.

The early years of the twentieth century saw the heydays of the railways, by 1920 there were 3,500 miles of track in Ireland, it is said that there was not a town in the country that was more than ten miles from a station. With the advent of the internal combustion engine and with it the motor lorry, the railways came under increasing financial pressure. Road haulers able to collect and deliver door to door held a distinct advantage from a service point of view, consequently trade both passenger and freight drifted away from the railways, with the consequential loss of revenue preventing companies updating engines and rolling stock etc. resulted in the inevitable closure of many lines between the forties and sixties of the last century. One such was the Clougher Valley Railway in Ulster which opened in 1887 and closed in 1942.

Some of the steam locomotives used in Ireland were made at Crewe, England, on 15th December 1959 engine number 92250 "The Evening Star" was completed at the works it was the 7,331st and last locomotive built at Crewe.