A Powell-Mason cable car jumped the tracks while turning onto Powell Street just before midnight Sunday night, July 13, 2008, leaving at least four people injured.
I assumed they were, you know, attached.
Which led to me learning about that sand thing:
The track brake does the lion's share of the work. The friction between wood and steel is what primarily stops the car. Make that dry wood and dry steel. Wet equals slick... this is not good.
This is where sand comes to the rescue. A small pedal on the floor is pressed to drop sand on the rails. The wheels crush the sand into powder, the powder soaks up the moisture and provides -- the magic word -- friction!