- Historic Sites
A Century of Cable Cars
Magnificently impractical and obsolete almost as soon as they were built, the cable lines briefly dominated urban transportation throughout the country
April/may 1985 | Volume 36, Issue 3
The project was highly experimental, and Hallidie decided to use wood liberally in the construction to save money. The cable conduit below the street was built of wooden planks, carried by castiron frames placed about five feet apart. Two parallel beams, also supported by the iron frames, formed the narrow slot in the surface of the street through which the cable gripping apparatus passed. Wooden timbers supported the conduit frames and running rails, and the street surface between the rails was covered with planking. Durable California redwood was used in all street construction.
The cable itself was an endless wire rope, three inches in circumference, made up of crucible-steel wires formed into six strands of nineteen wires each. Grooved pulleys placed in the conduit about forty feet apart carried the moving cable; huge horizontal pulleys in vaults below the street reversed its direction at the end of the line. The cable entered the powerhouse at right angles to the track and wound several times around an immense drum powered by a thirty-horsepower reciprocating steam engine. At the end of the line the cable passed around a large pulley mounted on a movable tension carriage whose 3,300-pound counterweight maintained a constant tension on the cable and helped to compensate for changes in its length brought about by variations in temperature and load.
The gripping mechanism, or “grip,” devised by Hallidie used a vertical slide, moved up and down by a handwheel and screw, to work a wedge-shaped block beneath the car. As it rose and fell, this wedge opened or closed two jaws around the cable. As the jaws shut on it, the cable would slip through them enough at first to let the car accelerate gradually to the cable speed, rather than starting with a jolt.
On Hallidie’s line the grip mechanism was mounted on a small, four-wheel open car called a dummy, which pulled a closed passenger car. Turntables at each end of the line rotated the cars for their return trip.
Months dragged by while Hallidie and his associates tried to raise the hundred thousand dollars needed to build the road. Ground finally was broken on June 2, 1873; under the terms of their franchise, the builders by then had just two months left to complete the entire line. Not until August 1, the last day before expiration of the franchise, was all in readiness for a trial run.
The little group of promoters gathered around Hallidie’s cable car at about 4:00 A.M. on that foggy summer morning. According to yet another of those tales that seem to attend such events, the gripman selected to run the car for the first time was an old locomotive engineer named Hewitt. He took one look at the steepness of the Clay Street slope and turned to Hallidie: “I think perhaps you had better take this down, boss.” So the inventor himself operated the car on its maiden trip.
He set off down the hill without incident and came back up again smoothly, stopping along the way to demonstrate the effectiveness of the grip mechanism.
It all went perfectly, and at the end of his inaugural run Hallidie stepped down to the quiet congratulations of his shareholders. “The operation was a serious one,” he noted at the time. “There was no frivolity. The whole affair was serious, and when it was done there was simply a mutual hand shaking and nothing but cold water drunk. 1 do not know whether I felt more rejoiced at the visible proofs of the success of the trial trip, than at the expression of satisfaction, relief and renewed confidence in the faces of the gentlemen who had invested the money and faith in the enterprise, and had stood by it so faithfully.”
“At five o’clock this morning the first car on the Clay Street Railroad was sent down the hill and back again by means of the wire rope,” reported the San Francisco Daily Bulletin later the same day. “It was a platform car, or dummy, loaded with men and boys. No difficulty was experienced in stopping it at any point desired. The success of the experiment was greater than the projectors anticipated. This evening between five and six o’clock a passenger car will be attached to the dummy and put on the road, but regular travel will not be attempted at present.”
A large crowd, which included such San Francisco notables as Mayor William Alvord, Chief of Police Patrick Cowley, and Fire Chief David Scannell, gathered on Clay Street for the afternoon’s run. With the cars poised for the first uphill trip, the crowd piled aboard, everyone eager to be among the first riders. About halfway up the hill, at a point where the grade was particularly severe, the cars, choked with sixty or more passengers, came to a halt. The freshly tarred cable was slipping on the powerhouse driving drum. Sawdust and a slight increase in cable tension solved the problem, and the cars resumed their journey without further difficulty.
Regular operation started on September 1, and the pioneer enterprise quickly established itself as a solid success. By the following February the cable cars were transporting more than 76,000 passengers a month; by 1875 there were 150,000. Four years after it opened, the line had proved so successful that it was extended west to Van Ness Avenue.