BELOW STREET LEVEL

Out on the street along their routes, the cable cars travel on steel tracks set above a channel enclosing the cable. At the top of the channel is a slot through which the cable car’s grip grabs the cable moving below. This distinctive feature of cable railway gave its name to a large district south of Market Street, the large business thoroughfare running on a diagonal southwest from the Ferry Building on the Embarcadero to Twin Peaks. Early cable car lines competed for space down the center of the street, and everything to the south of this was referred to by locals as “south of the slot”, a nickname that lives on with longtime San Franciscans.

The track structure not only supports the tracks themselves, but also the cable and the cars. This is accomplished through a series of yokes, spaced at intervals along the track, and made of steel set in concrete; formerly paving stones were set at street level between the tracks and slot, again after 1982 concrete casing was used exclusively. Carrier pulleys spaced every fifteen feet support the wire rope in the channel. Original channels along the Clay Street Hill Railroad were constructed of redwood planking and cast iron yokes to keep the building costs to a minimum. Later extensions and new cable companies utilized concrete and heavier iron yokes to strengthen and extend the life of the channels.

The system contains a variety of pulleys used for different purposes along the line. Access to these pulleys is gained through a service plate located on the street above. A crown pulley is simply a larger version of the carrier pulley, but of a greater diameter because of the greater strain on the cable at the crest of a hill. Neither type of pulley impedes the progress of the cable car; the grip and cable are lifted as they pass and then the cable falls back onto the pulley after the car passes.

Other pulleys are a bit more complicated in design and function. Depression bar pulleys are used to keep the cable down at the bottom of a hill; otherwise it would rise out of the slot. This necessitates placing the pulleys on top of the cable, but then the grip encounters interference as it tries to pass. To solve this, the depression pulleys are connected to a depression bar which pivots aside as the pulleys are freed by the passing grip, then swivels back into place after the car has passed. Access to this bar, like the carrier pulleys, is through a large steel plate in the street.

Another type is known as the stationary depression pulley. This arrangement requires the cable car gripman to release the cable from the grip as it passes over. Steel plates or bright yellow lettering painted on the street warn the gripman to “Let Go”. Letting go of the cable is necessary when two cables intersect at a crossing, the car passes a particular type of turn called a let-go curve, or when the gripman must release one cable and pick up another. If the gripman did not “let go”, then substantial damage would be done to the cables and grip itself.

To keep this from happening, these points have a bumper bar and bell feature to ensure safety and prevent damage to the system. If the grip is not “dropped” at the Let Go notice, then the cable will raise the bumper bar, dropping counterweights, and turning the pulley against the cable, which rings an alarm bell to alert the errant gripman to drop the cable. If for some reason the cable is still not dropped, then the bumper bar forces the cable out of the grip, causing damage however to both grip and cable, but preventing more serious and extensive damage to the system. The powerhouse is then notified of the incident and inspects for damage to the cable.

While snapped cables are very rare, the occasion broken strands do occur. In this situation the cable must be fixed immediately, because a broken strand caught in the grip has been the cause of accidents in the past.

At the powerhouse, the cable passes through a strand alarm, which catches protruding strands and sets off an electric gong, notifying the crew, who can then repair the damage.

Once the car has cleared the let-go, the gripman must pick up the cable again. After the let-go point, there is a dip in the tracks, which enables the grip to grab the cable without stopping. Another method is to use the cable lift level, at terminals or areas where the track dip is not available. The car operator lifts up the level and the pulley in the slot raises the cable into the grip. When some cars employed a side-grip however, then a lift rod was raised using a chain, causing the cable to slide down into the side of the grip. This arrangement is called a “gypsy chain” and is operated by the conductor after the car crosses the intersection. The last company to use a side grip was the California Street Cable Railroad, and after the Municipal Railway acquired it in the 1950s, the grips were changed to the now universal bottom grip used by the other lines.

In the heyday of cable car transportation, there were many crossings involving two cables; the Omnibus line as the last one built in San Francisco held the inferior position at all crossings and the Ferries & Cliff House Powell cable car had to drop rope 14 times along its route. Today, the only intersection where cables cross is at the crest of Powell Street, at California. Here a small stationary depression pulley holds the Powell Street cable under the intersecting California Street cable, a holdover from the era when different cable car companies competed against one another, and the original franchise along a street took precedence at intersections. If the cable car fails to coast all the way through the intersection, it is impossible to pick up the cable again without pushing the car beyond this point. The gripman must have clear right-of-way before entering the intersection so that he can coast through without stopping.

This accounts for the little signal house at the intersection of Powell and California. The signal house man shines a green light if the intersection is clear of cars and a red one if another cable car is approaching it. This way both operators know if they have clear passage, thus avoiding obvious problems. Even in modern, congested City streets, most drivers know the hazard of tangling with cable cars and give them a wide berth and grudging respect.

The procedure by which a cable makes turns was conceived in the early years of cable expansion throughout the City. At first, lines like the Clay Street Hill Railroad and the California Street Railroad were simply straight routes without any turns. This was the standard until 1880, when a new and often-expensive innovation made turns possible along a route. Prior to this time, companies like the Ferries & Cliff House employed only “let-go” or “drift” curves, where the grip released the cable and coasted around the turn. Of course this was only practical where two streets descended as the cable car approached an intersection.

Then in 1883, the Sutter Street Railroad introduced pull curves, invented by George Duncan for the Dunedin & Roslyn Tramway Company of Dunedin, New Zealand. This type of curve could be installed at any intersection, regardless of street physiognomy. The pull curve involved a series of many small pulleys holding the cable in place as it makes the turn. When the car approaches, the grip is pushed away from the pulleys and guided by a chafing bar set above and outside the pulleys, negotiates the turn. After the turn is completed, the cable returns to its usual position on the pulleys.

This type of curve is recognizable by the series of access plates abutting one another around a turn. All of these turns have given rise to the colorful shout of the conductor: “Look out for the curve”, often parodied by writers as a brassy Brooklyn dialect, although it is more likely to have been a Mission district accent at the time, similar in tone, yet distinct—and almost extinct in modern San Francisco.

Finally, the cable car system employs two types of terminal arrangements for sending cars back up their route. The California line uses a double-ended “California Car” with identical machinery on either end, except for the grip, which fastens to the opposite lever by a connecting rod. This allows the car to proceed back on its route from either terminal without turning the car physically around. Instead the car uses a system of switchbacks and crossovers on the tracks to set up the cars for a return trip. This arrangement was used on early cable car lines, like the Clay Street Hill Railway, to facilitate changing direction. The California Street Cable Railroad used this on the California street line and continues to do so to this day.

The so-called combination car used on the Powell and Mason lines has only one set of levers and grip, and so this necessitates use of a turntable. The gripman lets-go the cable and the car coasts onto the turntable. It is then turned around by manpower, much as it has since the 19th century. In early days and up until the 1970s, many in the crowd at the terminal assisted in helping the conductor and gripman—in the process getting the best seats before the others waiting at the stop. This practice was discontinued and now crowds wait orderly in line while the conductor and gripman work alone.

The turntable is a set of wooden planks atop a steel framework set on steel rollers and encased in a concrete foundation. The cable passes behind the turntable on a steel sheave and is directed around under the tracks again for the return journey. There are four turntables in the system, located at terminals on Market and Powell Streets, Hyde and Beach, Bay and Taylor, and one in the powerhouse at Mason and Washington Streets for directing cars out onto the line.

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the Street