There is a nice little book on this line from South Platte Press titled Rails to the Rosebud. From memory: the line started in Norfolk in the 1880's and in fits and starts made its way up through northern Nebraska in the 1890's and into South Dakota in 1906-1910. The line expanded ever northwestward as former reservation lands were opened for settlement. The line reached the Winner, SD in 1910 and stopped. In 1929 the CNW extended the line 30 miles to the northwest, reaching the small town of Wood, SD. In the early 20th century the line hauled settlers and their homesteading supplies and afterwards hauled mostly grain. In 1969 the CNW abandoned the 29 mile extension from Wood to Winner. In the mid-70's service had become very intermittent and carloads dropped as service became increasingly unreliable. In 1978 after failed efforts by shippers to save the line, the entire line was abandoned and the last 4 cars of scrap metal from Winner were hauled back to Norfolk in a very slow two day journey.
Source: Rails to the Rosebud, South Platte Press, 2008.