Chicago Burlington and Quincy 4978 is the youngest survivor of the O-1a class mikados. They often replaced older 2-8-2 Mikados where more power was required. The heaviest Mikados were the Great Northern's class O-8, with an axle load of . In 1904, the Central South African Railways (CSAR) placed 36 Class 11 Mikados in service. In 1934, Lima Locomotive Works delivered 25 22RA tenders to the NKP for Mikados. Some local industries still actively use Mikados on freight service.