 The locomotives were intended for light branch line work and they made their mark on the lightly laid Kerry line, gaining the name "Kerry Bogies" although they were also used on the Cork to Youghal line and as an assisting engine on the steeply graded (1 in 60 / 1.7 %) section of the main line from Glanmire to Blarney, this latter work taxing their capabilities to the limit.Mechanically they were the first bogie locomotives to have used the American principle of the "swing-link" bogie where hinged links control the truck's lateral (sideways) movement.Many changes took place during the long life of these locomotives, which lasted almost to the end of steam traction on the Córas Iompair Éireann (CIÉ).