Chronology of the Railways
In Ireland.

1834
December 17 First railway between Dublin and Kingstown now Dun Laoghaire opened.
1839
Great Northern Railway (Ireland) (GNR(I)) incorporated 1876 (the Ulster Railway, one of its constituents, dates from 1836) first section opened 1839, 606 miles (970 km)
Line opened between Belfast and Lisburn Co Antrim.
1841
The Belfast to Lisburn line is extended to Portadown Co Armagh
1844
May 24 The Dublin to Droheda line opened.
1845
Total length of line in Ireland 70 miles.
1846
The railway arrived in Bagenalstown Couinty Carlow
The gauge of the Ulster railway was altered.
1848
The first section of the Belfast to Ballymena via Carrickfergus line was built.
2nd August Line opened between Belfast and Hollywood in Co Down.
1849
The Belfast to Portadown line is extended to Armagh.
1850
Cork, Blackrock and Passage Railway 16 miles (26 km); (originally Irish gauge, 5 ft 3 in (1,600 mm), converted to 3 ft 0 in (914 mm) gauge in 1900); incorporated 1846, four locomotives, 57 other vehicles
A line to Newtownards via Dundonald in Co Down is opened. Images from Newtownards station.
1853
Waterford and Tramore Railway 7.25 miles (12 km); opened 5th September 1851, four locomotives, 32 other vehicles;. The line which was unique in that it was not conected to any other line, it closed, on 1st January1960
The Londonderry and Coleraine Railway was completed.
1855
The Ballymena, Ballymoney, Coleraine, and Portrush Railway was opened.
1857
The gauge of the Dublin to Kingstown railway was altered.
1858
Ballynahinch is connected to Downpatrick Co Down.
1860
A viaduct over the River Bann at Coleraine built.
1861
A line from Bangor County Down reaches Donaghdee in the same county.
1863
Londonderry and Lough Swilly Railway (L&LSR) 83 miles (133 km); {3 ft 0 in (914 mm) gauge}; opened 1863/
Extended in 1904 18 locomotives, 311 other vehicles
Dundalk, Newry and Greenore Railway 26.5 miles (42 km); incorporated 1863; six locomotives, 230 other vehicles
December 31 Line opened between Derry and Farland Point.
1864
A branch to Buncrana built from the Derry to Farland point line.
1865
The Belfast to Hollywood line extended to Bangor.
1869
Newcastle is connected to Downpatrick Co Down
1882
Sligo, Leitrim and Northern Counties Railway 49 miles (78 km); {4 ft 8½ in (1,435 mm) gauge}; incorporated 1875 11 locomotives, 228 other vehicles;
Closed 1957
1880
Giant's Causeway, Portrush and Bush Valley Railway & Tramway 8 miles (13 km); {3 ft 0 in (914 mm) gauge}; incorporated 1880; two locomotives, 23 other vehicles
Ballycastle Railway 16.25 miles (26 km) {3 ft 0 in (914 mm) gauge}; incorporated 1878, four locomotives, 74 other vehicles
A station was opened at Abbetydourney Co Kerry on the Tralee to Limerick line.
1883
An extension to Letterkenny was constructed from the Derry line 16 miles (26 km); worked by L&LSR
1884
Castlederg and Victoria Bridge Tramway 7.25 miles (1 2 km); {3 ft 0 in (914 mm) gauge}; incorporated 1883, three locomotives, 34 other vehicles; closed 1933
Bessbrook and Newry Light Railway (electric) 3 miles (5 km) {3 ft 0 in (914 mm) gauge} one locomotive, 24 other vehicles
1885.
The Letterkenny network was converted to narrow gauge.
The Great Northern rail system reaches Belturbet in Co Cavan as does the Cavan & Leitrim narrow guage system in June
1886
Clonakilty Extension Railway 8.75 miles (14 km);
Worked by CDJC
Clonakilty Extension Light Railway 8.75 miles (14 km); {3 ft 0 in (914 mm) gauge}; incorporated 1881.
Cork and Macroom Direct Railway 24.5 miles (38 km); incorporated 1861 four locomotives, 132 other vehicles
Listowel and Ballybunion Railway 10 miles (16 km); (Monorail) (Lartigue system); incorporated 1886, opened 1888; three locomotives, 39 other vehicles
1887
Tralee and Fenit Railway 8 miles (13 km)
Clogher Valley Railway 37 miles (59 km) {3 ft 0 in (914 mm) gauge}; incorporated 1884, seven locomotives, 127 other vehicles; closed 1942
West Clare Railway 27 miles (43 km); {3 ft 0 in (914 mm) gauge} eight locomotives, 146 other vehicles
Worked by CB&SCR
1896
1st August A 5 mile sput line connecting Ardee in Co Louth to the Belfast - Dublin line was opened
1887
Carrickfergus Harbour Junction Light Railway 1 mile (2 km); incorporated 1882,
Cork and Muskerry Light Railway (C&MLR) 18 miles (29 km); {3 ft 0 in (914 mm) gauge}; incorporated 1883, six locomotives, 87 other vehicles.
The West Clare Railway opened it closed 1961
1888
Dublin and Blessington Steam Tramway 15.5 miles (25 km); {5 ft 3 in (1,600 mm) gauge}; incorporated 1887, four locomotives, 46 other vehicles
Cavan and Leitrim Light Railway 48.5 miles (78 km); {3 ft 0 in (914 mm) gauge}; incorporated 1883, nine locomotives, 167 other vehicles
1889
June 12 Eighty passengers killed on the Armagh to Warrenpoint line.
1890
Loughrea and Attymon Railway 9 miles (14 km)
Worked by NCCMid {4 ft 8½ in (1,435 mm) gauge}
Ballinascarthy Railway; worked by T&CR; {3 ft 0 in (914 mm) gauge}; incorporated 1888.
1891
Timoleague and Courtmacsherry Railway (T&CR) 9 miles (14 km); {3 ft 0 in (914 mm) gauge}; incorporated 1888, two locomotives, 119 other vehicles
Tralee and Dingle Light Railway 37.5 miles (60 km); {3 ft 0 in (914 mm) gauge}; incorporated 1884, opened 1891; eight locomotives, 108 other vehicles
City of Dublin Junction Railway 1.25 miles (2 km)
1892
Ballinrobe and Claremorris Railway 12 miles (19 km)
Ardglass is connected to Downpatrick Co Down.
1904
New Ross and Waterford Extension Railway 13.5 miles (22 km)
Worked by GNR(I)
1909
Castleblayney, Keady and Armagh Railway 18.25 miles (29 km)
Worked by GSWR {4 ft 8½ in (1,435 mm) gauge}
Strabane and Letterkenny Railway 19.5 miles (31 km)
Worked by D&SER
1906
Castlewellan is connected to Newcastle.
1920
There are now about 3,500 miles of line in Ireland
1921
Jan 21st. First train arrives at Castlecomer (Co Klkenny)
1922
During the Civil War lines were lifted and bridges blown up.
1924
A Viaduct replacing one built in 1860 is built over the River Bann.
1925
The Great Southern came into existence it took over 26 other companies and employed over 15,000 workers.
1930-2
The Boyne viaduct is rebuilt it has a total length of 1,760 ft. with 15 spans.
1931-34
The Greenisland Loop, between Belfast and
1934
3rd June The Line conncting Ardee to the Belfast- Dublin line ceased carrying pasengers, freight was carried until 1976.
1948
All railways in Ulster are nationalized.
1950
All routes except the Belfast to Bangor and Belfast to Dublin lines are closed.
3 July The Limavady to Dungiven line was closed.
1951
31st Dec The Dublin-Greenore-Newry Railway closed after 78 year service.
1955
2 May 1955 A branch line to Limavady from the Belfast, Derry line was closed.
1950
3 July The Limavady to Dungiven line was closed
The Belfast to Newtownards via Dundonald line is closed.
1953
8 August The Letterkenny to Derry line closed.
Tralee to Dingle Light Railway closed.
1955
2 May . The spur line from the Belfast, Derry to Limavady was closed
  Passenger Service ceased in 1950's
1957
30 September The Omagh to Enniskillen line closed.
1959
March The Cavan & Leitrim Railway narrow guage, and the Great Northern railways closed.
1961
The West Clare railway closed.
1962
Castlecomer station closes (Co Klkenny)
1976
3rd November The line connecting Ardee to the Belfast - Dublin line was closed