The Córas Iompair Éireann 141 class locomotives were delivered in November and December 1962 from General Motors Electro Motive Division (EMD), the first consignment being unloaded at the North Wall, Dublin on 22 November. They were numbered B141 to B177 and were an updated version of the earlier 121 Class locomotives, mechanically very similar but with cabs at each end.
They are EMD model JL8 (J = Double Ended Cabs, L = Lightweight Frame, 8= 8-cylinder 567 engine) and although originally fitted with a EMD 8-567CR engine of , all were later fitted with 645 type "power packs" (piston & liner assemblies) for parts standardisation. The original power output was kept for reliability reasons. They weighed 67 tonnes and had a maximum speed of . Many of these locomotives were later rebuilt with a GM 8-645E engine of (as used in the re-engined Class C locomotives), though some have since had the original engine refitted. The locomotives were delivered in the new livery of brown/black/white. Following crew training trials between Inchicore and Monasterevin (passenger trains), Kildare (goods trains), and Hazelhatch (light engines), the class appeared on main line trials from Amiens Street (Connolly) to Drogheda, and Westland Row (Pearse) to Arklow on 4 December 1962, entering traffic on the Dublin to Cork main line four days later. The locomotives were fitted for multiple working and double-headed the 10:40 Dublin to Cork train and the return Cork to Dublin at 15:30. These were the heaviest trains at that time. From 10 December 1962 one locomotive was allocated to the Dublin–Belfast "Enterprise" link.
In later years, regular passenger duties included trains on the Rosslare to Waterford/Limerick lines, until they were superseded by railcars on these duties.
They are now almost exclusively used on Permanent Way trains and as pilots, with the odd very rare appearance on passenger services.
The current situation is shown below:
The following locomotives remain in service, all others have been withdrawn or scrapped:
141, 142, 144, 146, 152, 162, 163, 167, 171, 173, 175 and 177
The Irish Traction Group has a fund set up for the eventual preservation of a member of this class
Murphy Models commissioned Bachmann to produce an '00' gauge model of these locomotives Theses models were first released in early 2008.