This subseries includes the service records of many Copper Range Railroad Company employees in two overlapping sets of index cards (1900-1937 and 1902-1967). Additional service record books and files provide further coverage of varying degrees of comprehensiveness, particularly of the Mechanical Department. Earnings records, insurance records, medical records, and seniority rosters are also included in this subseries.

This subseries includes the service records of many Copper Range Railroad Company employees in two overlapping sets of index cards (1900-1937 and 1902-1967). Additional service record books and files provide further coverage of varying degrees of comprehensiveness, particularly of the Mechanical Department. Earnings records, insurance records, medical records, and seniority rosters are also included in this subseries.