The C class were placed into service initially in Auckland, Wellington, and Christchurch although some locomotives did spend short periods of time in Dunedin following overhaul at Hillside Workshops or as a short-term allocation following their completion. It was found that while the C class were extremely capable, the locomotives were insufficiently heavy enough to move some of the larger trains being shunted. This led to the conversion of the BB class 4-8-0s to shunting and branch line service in order to replace the C class on these heavier duties. During their service life, the C class occasionally handled suburban trains with the Wellington-based examples doing so at times over the Hutt Valley line. The Auckland-based locomotives tended to do so only on the
Onehunga Branch, while the Christchurch-based locomotives did so infrequently. It was not unknown for the Christchurch-based examples of the C class to work further afield and members of the class have been noted as working the Little River, Methven, Oxford, and Whitecliffs branches, as well as occasionally handling race trains to Sockburn. Due to the arrival of the
DS class and
DSB class diesel shunters in 1955, the Wellington locomotives were displaced and sent to Auckland and Christchurch. Of the twenty-four, twelve were withdrawn in 1963-64 but the other engines continued running until 1968 by which time only Christchurch had a permanent allocation. During World War II, the decision was made to fit several Wellington-based engines, particularly of the C class, with fire-fighting pumps in case of a Japanese air raid. At least one locomotive, C 849, was so fitted but the boiler-mounted pumps were not successful and relied on sufficient water supply from the locomotive's boiler to function. Following the cessation of hostilities, these pumps were quickly removed. ==Withdrawal==