The Córas Iompair Éireann 181 Class locomotives were built in 1966 by General Motors Electro-Motive Division (EMD) and numbered B181 to B192.

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,[1] weighed 67 tonnes (66 long tons; 74 short tons), and had a maximum design speed of 143 km/h (89 mph) which was restricted to 120 km/h (75 mph) in service.

Number 186 was later fitted with an EMD 8-567CR engine of 960 hp (720 kW), as used in the 141 Class locomotives.

[2] The last was 190 in November 2009 and has been preserved by the Irish Traction Group based at the West Clare Railway.