Partition of Ireland
Beginning on 21 January 1919 with the Soloheadbeg ambush, through the Irish War of Independence, Irish republicans attempted to bring about the secession of Ireland from the United Kingdom of Great Britain and Ireland. Meanwhile, Irish unionistsmost of whom lived in the northeast of the islandwere just as determined to maintain the Union. The British Government, committed to implementing Home Rule, set up a cabinet committee under the chairmanship of southern unionist Walter Long. The Long Committee recommended the establishment of two devolved administrations, dividing the island into two territories: Northern Ireland and Southern Ireland. This was implemented as the Government of Ireland Act 1920. The act entered into force as a "" on 3 May 1921 and provided that Northern Ireland would consist of the six northeastern counties, while the remainder of the island would form Southern Ireland. It was intended that each jurisdiction would be granted home rule but remain within the United Kingdom. The government of Southern Ireland never functioned: the war for independence continued until the two sides agreed a truce in July 1921, ending with the Anglo-Irish Treaty on 6 December 1921.
Multiple units of Ireland
NIR purchased a Windhoff Multi-Purpose Vehicle for use as the Rail Head Treatment Train, equipped to lay sandite and high pressure water. The MPV was procured to replace a converted Class 80 unit.
The Great Northern Railway (Ireland) straddled the border between the Republic and Northern Ireland, and so was not incorporated in either the CIE or UTA. However, mounting losses saw the network purchased jointly by the Irish and British governments on Tuesday 1 September 1953. It was run as a joint board, independent of the CIE and UTA, until Tuesday 30 September 1958 when it was dissolved and the remaining stock split equally between the 2 railways.