What Are CFCs? CFCs are short for the compound, chlorofluorocarbon, which contain carbon, chlorine, and fluorine. Chlorofluorocarbons are more commonly referred to as CFCs or, when used for refrigeration, CFCs are also known as freon. Developed in the 1930s as a safe alternative to ammonia, usage of CFCs grew rapidly because of its usefulness and convenience throughout most of the 20th century.
Great Northern Railway 1893-1925 The first route over the pass was a series of switchbacks, with grades of up to 4 % on the West side and 3.5% on East side, was completed on January 6, 1893 (see photos below). To traverse a switchback the train has to travel to the end of the dead end spur, then the switch is thrown and engine reverses
Great Northern Railway (U.S.) GN's 4-8-4 S-2 Northern class locomotive #2584 and nearby sculpture, U.S.âCanada Friendship in Havre, Montana. The Great Northern Railway (reporting mark GN) was an American Class I railroad. Running from Saint Paul, Minnesota, to Seattle, Washington, it was the creation of 19th-century railroad entrepreneur James J. Hill and was developed from the Saint Paul & Pacific Railroad.