Built after the fire of 1906, this signal tower guards the crossing of the Powell Street cable car line and California Street cable car line on their namesake streets in San Francisco, California, on March 6, 2003. It is a complicated operation, not just because of the track, but because one cable has to pass under the other. Since the Powell line was built nine years after the California line, superiority was established by seniority. Powell cars coast across the crossing, while California cars remain attached to the cable. A signal tower operator uses pushbuttons to control colored signal lights directing movements through the crossing. Who goes first? Former Muni employee Emiliano J. Echeverria wrote in a story about his two years as operator in the tower, “A Cal car is sitting at Stockton waiting for his 'green'. You let Stockton Cal car go 'cause his run is the longest to traverse from Stockton past Powell. In rainy weather only: never let a Powell car cross California Street until the Cal car descending from Mason has come to a complete stop. Sometimes the cars slide across the intersection!”
