The City by the Bay ’s cable’s length cars are more than just a San Francisco dainty , they ’re the last such manually - engage trolleys in existence . And these massive engines are what keep them chugging up some of the City ’s steepest terrain .
The heart of the cable’s length railroad car organization is the Powerhouse located at the corner of Washington and Mason Streets . Each of the trolley line — California Street , the Powel - Hyde , Powel - Mason , and their common discussion section — all emanate from this terminal hub . Each strain is severally powered by a 510HP ( 380 kW ) DC electrical motor and include speed - reducing gears and three large , self - adjust pulley block called bundle . The gears crop to normalize the cable ’s speed to 9.5MPH across all lines while the sheaves ensure the cables run through smoothly .
The cable itself is a 1.25 - column inch diameter brand rope comprised of six twisted strands , each of which are made of 19 individual wire encircling asisal ropecore . The cables vary in distance from 9,300 feet on the Powell line to 21,700 feet for the California . Each cable is slathered with a Jack - like substance that works much like axle grease , wearing and breaking down in the cable length ’s plaza . Even with this protective software , the cables only last six to eight months on average . When one fails , the system is shut out down that evening and a new cable is tie into the provender .
According to the San Francisco Cable Car Museum ,
Each of the dissimilar cable car lines once had its own power plant -or sometimes several - to ram the overseas telegram used on the line . The first power sources were steam engines power by enormous amounts of ember each 24-hour interval , thus each human dynamo was equipped with steam boiler to heat the water need to produce steam . During the decennary after the 1906 temblor , steam power was replaced by electrical energy . Before the 1982 return , a individual 750 horsepower galvanic motor drove all the three remaining cable system short letter , with another identical motor for backup .
After refurbishment , four 510 horsepower locomotive engine were installed , one for each cable with its own separate gear case . A set of six 14 - foot diameter sheaves is drive by the motor , around which the line run in a figure - eight shape to reduce slippage . latent hostility sheaves keep a unremitting tensity on the cable and takes up slack produced by wear , motorcar onus and stoppage of cars on the argument .
From the tension sheave the cable moves back under the office bundle into an wrap channel through which it passes out of the powerhouse and under the street to the tracks .
The individual cars grasp the running cable in what are essentially a gargantuan pair of pliers that poke through the bottom of the car and extend under the street to the cable track . The gripman — aka the driver — controls the railcar ’s forward momentum by varying how tightly the grip snap up the cable . [ SF Cable Car Wiki – Cable Car Museum1,2 ]
Image : Caroline Culler
San Francisco
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