2 August: San Francisco's cable cars

The first trial run of a San Francisco cable car took place on this date in 1873. Here are 10 things you might not know about San Francisco's cable cars.

1. The San Francisco cable car system is the world's last manually operated cable car system. There used to be similar systems in other cities, including London, but by 1955, all the London ones had been replaced by Buses and cars.
2. The cable car was invented by an engineer called Andrew Smith Hallidie, who saw a need for such a system after witnessing an accident where a streetcar drawn by Horses over wet cobblestones slid backwards, killing the horses.
3. The driver of a cable car is known as a gripman or grip operator. They are called that because they operate a lever which grips or releases the cable. It's a highly skilled job, as the grip operator needs to know the places where cables cross each other or don't follow the tracks, in order to coast over them, and they need to be able to anticipate and react to what other traffic is doing. The job calls for great upper body strength needed for the grip and brakes, as well as good hand–eye coordination and balance.
4. Grip operators were always men until 1997. No woman had ever managed to make it past the first day of training. In 1997, Fannie Mae Barnes, aged 52, completed and passed the 25 day course and became the first woman to operate a cable car grip in January 1998. Since then, another woman called Willa Johnson became a grip operator in April 2010.
5. Cable cars travel at a constant speed of 9.5 miles an hour (15.3 km/h).
6. When a cable car needs to be replaced, it takes several dozen craftsmen (carpenters, machinists, electric transit mechanics, painters, glaziers, pattern makers and transit operators) 18 to 24 months to build a new one.
7. The cables they run on are 1.25 inches (3.2 cm) in diameter and have six steel strands, each containing 19 wires. The cables are coated with a tar like substance.
8. Before San Francisco's Great Earthquake, there were 600 cable cars in San Francisco, running on 23 lines. Today, there are just 44, running on three lines: The Powell-Mason, The Powell-Hyde and The California Street.
9. 7 million passengers ride the cable cars each year, the majority of them tourists.
10. Every July the cable car crews hold a cable car bell ringing contest in Union Square.