English: Mechanism of a Union Switch and Signal style H-H2 signal with an inspection date of 6-10-44. The lamp and reflector assembly has been removed from the back of the mechanism, exposing the sector and the colored roundels inside. Light shining in through the front lens of the mechanism illuminates the red roundel. The red roundel is in the center and is the one displayed when no power is applied. Applying power will swing the sector either left or right to illuminate the yellow or green roundels. This mechanism was recovered from a signal along the Hoover Nature Trail, formerly the Rock Island Railroad, in West Branch, Iowa.