Re: High speed thrill
Author: SF Bill
Date: 12-04-2017 - 10:09
For those who want to know:
THE BRAKES
The cable cars employ a series of mechanisms to assist in braking the car and regulating its speed. The three parts of this system are the wheel brakes, track brakes, and an emergency brake.
Both front and rear wheels have metal brake shoes, which the gripman operated by means of a pedal located by the grip. The conductor also has a rear brake lever at the back of the Powell and Mason cars for use on steep grades, while the California car has two pedals, one at each end of the car.
Next to the grip and quadrant is a lever that operates the track brakes, pine blocks situated between the wheels. These blocks are pressed into the track whenever the gripman pulls back on the brake lever. The soft wood used exerts pressure on the tracks—sometimes enough to produce smoke—and stops the car. These blocks wear quickly and are replaced every three days or so.
The final brake device is an emergency brake, operated also with a lever near the grip and track brake levers. The brake itself is a one-and-a-half inch thick piece of steel, about eighteen inches in length, hanging under the cars and over the track slot. If the gripman cannot stop the car by other means, pulling on the lever will push the brake down into the slot where it wedges so tightly that it must often be removed with a torch. This action leads to it sometimes being referred to as a “guillotine” brake.
Of course these brakes are in many ways supplemental as the main braking action results from the cable itself, which when tightly held in the grip’s jaws enable the cable cars to move along at a nice 9.5 miles per hour constant speed, even on steep grades.