Cable car diamond The Powell Street cable car line and California Street cable car line cross each other on their namesake streets in San Francisco, California. 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. In this view, a California line cable car waits at the crossing while a Powell car coasts across the diamond.
