Frankton Junction had two signal boxes, the South Box was the largest signal box of the two, actually it was the largest signal box in New Zealand containing the largest mechanical interlocking frame in the country, including controlling the largest semaphore gantry, beginning at midnight on July 31 1910 and operational for a total of 77 years. The Box was decommissioned on the morning of 29 Nov 1987. (FSB)