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.
Most test runs were on the Dublin-Cork main line; two runs went to Cork and back, and others terminated at points between Hazelhatch and Portarlington.