Northern Pacific Railway class S 10

The Chicago Southern was incorporated in 1904 by John R. Walsh, to build part of a Chicago, Illinois to Terre Haute, Indiana line. Twelve 2-6-0, eight 4-4-0 and twenty 4-6-0 locomotives were ordered from the Rogers works of the American Locomotive Company in Paterson, New Jersey. The first six 4-6-0's were delivered in August 1905. The remaining fourteen were held, mostly complete, by the builder because the railroad entered bankruptcy. Two of those went to the Wisconsin and Michigan, and four to the Chicago Terre Haute and Southeastern - later the Milwaukee Road.

In 1907, the Northern Pacific was in need of some branch line locomotives, and purchased ten of the fourteen remaining at the builder's plant. The cost was $14,500 each. They became NP class S-10, numbers 320-329. Because they were completed in February 1907, that was the date on their builder's plates. Alco sold the remaining four to Pullman, the Nevada Northern, and the Manchurian Southern. The later was a Japanese-controlled railroad in Manchuria. They offered the NP $15,000 each for their ten, but the NP declined.

In May 1908, 321 and 322 were assigned to the Dakota Division, 320, 323 and 324 to the Pharaoh Division, and 325-329 to the Minnesota Division. By July 1925, 325 and 326 were reassigned to the Montana Division.

First to leave the roster was 329, scrapped at Brainerd, Minnesota in January 1929. More followed in 1930-1933, leaving only 321 and 328. These were kept for the branch lines from White Bear Lake, Minnesota to Stillwater, Minnesota, Wyoming, Minnesota to Taylors Falls, Minnesota, and Rush City, Minnesota to Grantsburg, Wisconsin. The primary reason was that the light bridge over the St. Croix River on the Grantsburg branch could not support heavier locomotives. 321 was set to scrap at Brainerd in 1946. The Local operating on the Grantsburg Branch, from Rush City, was known as the "Blueberry Special."

328 had the honor of pulling the last train to Taylors Falls in June, 1948.