This railroad union was founded in 1894 in Kansas City, Missouri and in 1969 ended when it became part of the United Transportation Union. These buttons begin in 1906 and six of these up to 1911 are in celluloid. At that point the buttons became litho tin. Majority are 7/8” but in the later years typical size is 1-1/8” to 1.5”. There are no buttons between 1912-1928. The following years are then represented and if there is more than one button per year it is in parenthesis: 1929, 1931, 1935, 1937, 1938 (2), 1940, 1941, 1942, 1944, 1946, 1949 (7), 1950 (5), 1951 (9), 1952 (2), 1954 (3), 1955 (3), 1956 (6), 1957 (4), 1960 (2), 1962, 1964 (2), 1965 (7), 1966 (2), 1967, 1968. A few exceptions but vast majority are in Exc. to NM condition. 72 pieces in all.