The Córas Iompair Éireann 181 Class locomotives
were built in 1966 by General Motors Electro-Motive Division
(EMD) and numbered B181 to B192.
These locomotives were virtually identical to the earlier 141 Class
locomotives, but fitted with the more powerful 645
engine and thermostatically controlled engine cooling fan and inlet shutters. Delivery took place in 1966, with introduction into service happening a short time later.
They were fitted with an EMD 8-645E engine of 1100 hp, weighed , and had a maximum design speed of which was restricted to in service. Number 186 was later fitted with an EMD 8-567CR
engine of , as used in the 141 Class locomotives.
All of the 181 class have been withdrawn, the first being 191 in 1991 after a runaway incident at Clonsilla; it was later scrapped in 1998. The last was 190 in November 2009 and has been preserved by the Irish Traction Group
,. In their final days they were only used on Permanent Way trains or as pilots.
Murphy Models commissioned Bachmann to produce an '00' gauge
model of these locomotives. This model first was released in December 2007. It has been done in all four main liveries worn by the class.