The Magnetic Signal Company, formed sometime after 1910, received its first patent on May 19, 1914. Based in Los Angeles, it mainly sold crossing signals to western railroads such as the Santa Fe and Union Pacific, and Pacific Electric Railroad was the first railroad to use the wig wag signal. Griswold Signal Company later purchased Magnetic Signal Company, moved its headquarters to Minneapolis, and continued producing these signals and replacement parts into the 1960s. Very few original wig wag signals still operate in the United States. A Model 11, type KCR, had a special cage to protect the swinging arm from damage at a grade crossing. An approaching train activated the signal and kept it operating until the train had cleared, while a warning bell alerted motorists of the impending train. This signal could be activated by any of the three tracks it guarded at the crossing.