These blotters from the Dale Hastin collection were all issued by the Milwaukee Road before the war. The PDFs are 300 to 500 kilobytes in size.
The first one is the easiest to date as it advertises the 1933 Chicago Fair. It mentions the Sioux, which connected Rapid City, SD and Chicago from 1929 through Amtrak.
The next blotter encourages people to take the Southwest Limited from Madison, Wisconsin to Excelsior Springs, Missouri. The Southwest Limited began life as a Chicago-Kansas City train in 1903, but didn’t have a Milwaukee section (which would have served Madison) until 1932, so this blotter must be from that year or later.
This blotter lists three trains: the Southwest Limited (with the Milwaukee extension, making it post 1932); Pioneer Limited (which continued west from Omaha on the Union Pacific); and the Arrow (which continued west to Sioux Falls, SD on the Milwaukee).
This blotter is clearly from the early 1940s. The Chippewa began operating in 1937, while the Copper Country Limited began in 1907.