San Francisco’s Powell Street Cable Cars
When Stationary Steam Engines Powered the Cable

By Walter Rice Ph.D. and  Emiliano Echeverria

The authors wish to dedicate this article, on the occasion of the 125th anniversary of the cable car, to Andrew Smith Hallidie, who used the stationary steam engine to power the world’s first cable car line, the Clay Street Hill Railroad, August 2, 1873.
Ferry terminal Travelers arriving at the Union Ferry Depot at the foot of Market Street before the 1906 disaster would often see San Francisco engulfed in black clouds of coal smoke (shows in photo has white haze). Enter Market Street from Sacramento Street (far right) is Sacramento-Clay cable car, the cable of which was powered by the stationary steam engines of Washington-Mason. Walter Rice Collection. All rights reserved.

The smoke stack rises from the rear of the San Francisco Municipal Railway’s (Muni) Washington and Mason cable carbarn and powerhouse as a monument to the era when steam powered the Powell Street cable car system.  Service on Powell Street began on March 28, 1888, as part of the Ferries & Cliff House Railway Company (also called the Powell Street Railway), with full service on the Powell-Mason line beginning a few days later.  (This route has never been changed.)  At the same time, the company extended a route to the city’s Western Addition with the opening of the Powell-Jackson line.  The Ferries & Cliff House Railway in 1887 had built its carbarn and powerhouse  for the Powell Street lines at Washington and Mason Streets.  The location was where the two lines divided from their shared Powell Street trackage.

This site has been used ever since as the location for the cable carbarn and powerhouse--nowadays for the three Muni cable car lines.  In 1888, the Ferries & Cliff House Railway company  purchased the world’s first cable car line, the Clay Street Hill Railroad, to gain access to the Ferry Building--at the time, the most important public transportation terminal on the West Coast.  Initially,  the Clay Street line was torn up and replaced with single tracks on Sacramento and Clay Streets  east of Powell to the Union Ferry Depot. During a seventy-day period in 1891, this line was removed and replaced by  the new Sacramento-Clay  line.  The Washington and Mason powerhouse, also, provided the power for the cables for these operations.

The current building is the third cable carbarn and powerhouse at Washington and Mason Streets.  The original three-story structure was a victim of the April 1906 earthquake and fire.  The United Railroads, the operator since 1902, built a smaller “temporary” facility on the site from the destroyed remnants.  The building was rebuilt during the 1982-84 rehabilitation of the cable car system.

The principle of the cable car is simple.  Each cable car is equipped with a grip -- which is essentially a 327-pound pair of pliers -- that extends through a slot between the rails and grabs hold of the cable to pull the car along.  To move the car, the gripper pulls back on the lever -- "grabbing the rope," as it is called -- closing the jaws of the grip and forcing the two soft-steel dies in the grip's crotch to apply increasing pressure on the moving cable.  The farther back the gripper pulls, the greater the pressure (as much as 30,000 pounds per square inch), until the car is moving at the full speed of the cable — a constant 9½ miles an hour.  The grip completely lets go of the cable when the grip lever is released all the way forward allowing the gripper, by applying the brakes, to stop the cable car.

The solution to the problem of how to power the cable was clear to the architects of the original cable car systems.  Steam power was the center piece of the nineteenth century industrial revolution.  By the 1870s, the stationary steam engine had been perfected to a degree that it could be easily adopted to the requirements of the emerging cable railroads.  Accordingly, the Ferries & Cliff House Railway embraced the prevailing technology of the period--the stationary steam engine -- as its means of locomotion.
FCH Car 9 Ferries & Cliff House Company (Powell Street Railway) cable car No. 9 is brand new as it awaits another trip from Bay and Taylor Streets to Powell and Market on the then-new Powell-Mason line, 1888. The cables used for this trip would be powered by steam power from the Washington-Mason Power House. Walter Rice Collection. All rights reserved.

Full Steam Ahead

The edifice was imposing.  The Ferries & Cliff House Railway built a three-story brick and wood structure at Washington and Mason streets to house its general offices, powerhouse and carbarn.  A gracefully designed 185-foot  cylindrical smokestack gave testimony that steam powered the system.  This height was required to vent away the heavy black smoke produced by burning Welsh anthracite coal from the neighboring homes.

The ground floor had an area of slightly less than 19,000 square feet.  The company offices were in the front center.  There was an iron repair shop and blacksmith shop.  The majority of the ground floor space was devoted to the power equipment--cable winding machinery, stationary steam engines, boilers and coal bunkers.  The cable cars were stored and repaired on the second and third floors.

The cable winding machinery to power the cables was placed (as it is today) in a diagonal line across the building from the corner of Washington and Mason Streets.  This was necessary since the cable stretches several feet during its service life, and proper tension on the cable must be maintained. The tension was maintained by moving the rear drum (wheel, pulley or sheave [pronounced “shiv”]) farther back from the winding drums.  When this drum reached its farthest point, the cable was either shortened and spliced, or replaced.  The diagonal arrangement provided the maximum space for these tension adjustments.  The tension drum was on an  approximate 120-foot-long track.

Originally, the three cables required for the initial two lines were powered by two high pressure horizontal slide valve Corliss type Thompson non-condensing 24" x 48" stationary steam engines.  (Corliss type steam engines had a single cylindrical horizonal oscillating valve.) These were built by San Francisco's Golden Gate Mining Iron Works.  Each engine had  a horsepower rating of 450.  Because of the planned physical incorporation of the former Clay Street line into the Ferries & Cliff House Railway, coupled with a planned further westward expansion of its cable system and increased car requirements to meet expanding patronage, additional horsepower was required.

To meet this requirement, two additional Corliss type  non-condensing 25"x 44" stationary steam engines were placed into operation in February 1890.  Assembly of the these engines had taken place over the previous four months at the powerhouse.  In order to conserve space, the new engines were vertical.  Each had a horsepower rating of 500 and were manufactured by the Alliance Foundry Company of San Francisco at a cost between $18,000 and $20,000.

By the time of the merger of the Ferries & Cliff House Railway into the Southern Pacific controlled Market Street Railway in October 1893, the system boasted twenty-two miles of track, sixteen of which were cable operated and six by steam dummy.  Five separate cables were in use which were driven by three 14' diameter winding drums.  To keep the cable from slipping, each cable wrapped ¾ around a powered driving drum and under and over an unpowered idler drum in a figure-8 pattern.  The cable then turned around a rear-located tension drum.

The two horizontal steam engines were located in front of the winding and idler drums, near the Washington-Mason corner of the building.  The vertical engines were placed behind the idler drums.  Each pair of engines was connected to its own shaft to transmit the required energy to a large gear, which was connected to the winding drums.  Attached to each shaft was a 4' 6" pinion (gear) with V-shaped teeth which at the option of the powerhouse engineer, could mesh with the 14' gear wheel on the driver shafts.  By this arrangement either or both pairs of engines could drive the cables.

The three idler drums were actually three 15' diameter flywheels weighing twenty-five tons each.  These were used to regulate the uniformity of the cable speed.  A combination of the flywheel’s mass and ability to store energy did this.  Its stored energy was released when the weight on the cable increased as a car attached to the cable.  Without this release of energy the cable would slow.  When a car let-go from the cable, the cable would tend to speed up.  The flywheel’s mass would offset this tendency.

Steam was originally generated in tubular boilers with a total capacity of 540 horse power. In 1894, these were replaced by four batteries (each battery had two boilers) of elephant  boilers. (Elephant  boilers were water tube boilers that were boxed shaped as opposed to being cylindrical.) The Union Iron Works of San Francisco was the builder.  They had a horsepower of 920. The fuel source was imported Welsh coal, delivered by horse drawn drayage. It  was burned on Richardson grates with a forced draft.  The boilers and firing pit were at the rear of the ground floor.

The daily coal consumption was about ten tons.  At an average cost of $8 per ton in 1893, average fuel cost to operate the normal fifty-one cars was about $1.50 per car.  On Sundays and holidays ridership increased by 30,000 to 60,000 extra passengers.  Twenty to twenty-five extra cars were often required.  The additional coal consumption, amazingly, was less than a ton.

Farewell to Coal, Then Steam

Travelers arriving at the Union Ferry Depot at the foot of Market Street in the 1890s, would often see San Francisco engulfed in black clouds of coal smoke.   Yes, a century ago there were environmental problems and concerns.  The Washington-Mason powerhouse received continuous complaints from the neighborhood about the soot and dirt the  anthracite residue produced.  The Lackawanna Railroad’s mythical Miss Phoebe Snow, whose garments always remained stainless after riding an anthracite powered Lackawanna steam train, was not a Washington-Mason neighbor.

These concerns coupled with economic reality that coal was proving to be expensive compared to oil and electricity led to a conversion away from coal.  The Washington-Mason powerhouse was no exception.

Ironically, the 1901 conversion to oil brought electric traction to the Washington-Mason cable car and powerhouse.  In that year, the Market Street Railway created a single-track standard gauge (4' 8½") electrified connection on the west side of Mason Street by adding a third running rail to the narrow gauge (3' 6") cable car track (this track was used until February 1950).  This track connected the Washington-Mason barn and powerhouse and the electric street railway system at Broadway, two blocks north.  After 1907, this track was used to haul cable cars to the main railway shops located in the southwestern part of San Francisco.  The narrow gauge cable cars were hauled on a standard gauge flatcar.

Initially, this trackage was built  for the direct railway delivery of oil.  A 2,500 gallon oil tank car, No. 0201, was added to  the railway's non-revenue rolling stock. A second oil tank car, No. 0202 (in 1903, the numbers of these cars were switched), a two-cab 4,410 gallon capacity car followed.

The Market Street Railway built, in 1901, an annex on the north side of  Washington-Mason. The annex featured a six foot inset in the front to allow for the swing into the building from Mason Street of the oil tank car(s) and flat cars.

Oil storage capacity of 21,000 gallons was created at Washington-Mason.  To pump the oil from storage, two Hooker #6 feed pumps were employed.  The oil burning equipment was of the Morrissey type with the oil preheated, for greater efficiency, before entering the boilers by two Lewellyn feed water heaters.

At precisely six seconds after 5:12 a.m. on April 18, 1906, the Great Earthquake struck. Sixty hours later, after the fires had ceased raging, much of the city, including Washington-Mason,  lay in ruins.  The two Powell Street lines (the Powell-Mason and a shortened Washington-Jackson), and a shortened Sacramento-Clay line survived the earthquake and fire.  The Powell lines were reopened in 1907 and Sacramento-Clay in 1908.  These routes and the other cable line survivors shared one thing in common--steep hills.

Oil powered steam operation continued as before the earthquake and fire in a smaller "temporary" replacement at Washington-Mason.  The 185' smoke stack was  shortened to approximately 60' due to a major crack in the upper part of the stack.  The switch to oil, with its much lighter smoke, meant proper venting could occur with a much smaller smoke stack. (The only part of today's Washington-Mason which is original to 1887 is the smoke stack.)

Steam could not hold out indefinitely against the economies and reliability of electricity.  In 1912, a 600 horse power General Electric electric motor (serial # 454614) replaced the traditional vertical steam engines.  The horizontal steam engines, however, were still kept for "standby" service.

In 1926, all steam operation of the cable ended when a second complete electrical drive was installed.  The new motor was a 750 horse power General Electric product  (serial # 4562255). During the fourteen years from 1912, it had been necessary only occasionally to "fire up" the steam apparatus.  However, since it took between five and six hours to get sufficient steam up to power for the reciprocating engines, major service delays were encountered.

A year later, in 1927, a twenty year old  boiler was purchased to run auxiliary equipment.  This was  a 50 horse power HRT type 9' 10" boiler which was equipped with a Ray Oil Burner, a San Francisco product. During the 1982-84 cable car reconstruction, the last steam powered piece of equipment was removed--an unused  steam operated oil duplex transfer pump.
WM Smokestack The only part of today's Washington-Mason that is original to 1887 is the smokestack. The original 185-foot smokestack had been shortened to approximately 60-feet due to a major crack from the 1906 Earthquake. The smokestack is shown in 1983, during the 1982-84 rebuilding of Washington-Mason. Walter Rice Collection. All rights reserved.


Today, each of the four cables has its own drive machinery--a 510-horsepower DC electric motor, gears to reduce the speed of the motor to the proper cable speed, and a set of three sheaves. On the top of Washington-Mason is a large sign at the roof -- "Ferries & Cliff House Railway 1887" -- a testament to the Powell Street lines age of steam.

Click below to see a 1905 Washington/Mason floor plan

Plan: Washington/Mason Ground Floor


The authors would like to extend a special "thank-you" to Karl Hovanitz for suggesting this article and the late Richard Schlaich for his invaluable insights and generosity.

Published: Live Steam,  November/December 1998.

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Last updated 01-Jan-2005