6060's design is an extension of CNR Northern U-2-g design (4-8-4) which was able to run through divisional points where other engines would need to be serviced, and established performance records. One such locomotive ran 18,353 miles in one month, and it was typical for the design to run without change from Montreal, Quebec, to Halifax, Nova Scotia, for a total of 841 miles. As a result of being constructed during World War II when the need for more locomotives was high but the ready supply of iron was low, the U-1-f class of 4-8-2s, of which 6060 was the first, were lighter and more versatile locomotives than the U-2 Northerns. 6060 rolled off the erecting floor at Montreal Locomotive Works early in October 1944.