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canyons, days were consumed in finding a feasible path of ascent to
the summits of the cliffs.

Construction was started on September 1st, 1911, when the framing
of the timber for the towers on Section lY was commenced. While
the framing was in progress, new roads and trails were being built,
so as to command the location of the line. At a point on the railroad
about 3^ miles north of Iveeler an old charcoal road traverses the west
slope of Inyo Mountain to within a mile of the summit crossing.
The summit was connected to the old road by a new construction, and
the old road was repaired and made serviceable. However, at an ele-
vation of 5 900 ft., there was a stretch of about 330 ft. of road
having a grade of 25%, and the conditions were such that this grade
could not be eliminated or improved at a reasonable cost. Thus,
25% became the ruling grade for hauling the material needed for the
construction between Control Stations 4 and 1. The maximum load
which eight horses can haul on such a grade is about 5 000 lb. Heavier
loads required ten or twelve horses. As the distance from Owens
Valley to the summit was nearly 10 miles, a camp was established on
the road about 3i miles west of the summit. By this arrangement
teams could make one trip per day from the railroad to the camp,
leaving their loaded wagons for other teams, quartered at the camp,




Fig. 3. — Saline Valley and Structure 9. Anchorage and Tension Structure 11.




-Tramway Crossing Daisy Canyon, Control Station 3 to Structuee 16.
Line Rider on Carrier.




Fig. 5. — Bucket Leaving Luaui.vg Tek.min'al.




Fig. 6. — Loaded and Empty Carriers Passing on 80% Grade, Showing Vertical
Position Maintained by Both.



AEKIAL TKAMWAY FOR SALINE VALLEY SALT CO. 731

to haul to the summit and unload. The camp teams could make three
trips in 2 days. The total weight of material hauled from the
railroad to this camp was found to be 1.1 tons of grain, 5.4 tons of
hay, and 23.2 tons of water, for each 70.3 tons of material required for
the tramway construction. The maintenance cost of a team, consisting
of eight horses and driver, with headquarters at the railroad, was $15
per day. A team maintained at the upper camp cost $21 per day, the
increase being due to the fact that all feed and water used at the camp
had to be hauled from the railroad.

It was impossible to build roads on the east flank of the Inyo
Mountains. After a great deal of difficulty, a trail was constructed
over the summit to Saline Valley. As heavy machinery could not be
moved by pack animals, it was necessary to construct temporary, double-
cable, reversible tramways for this purpose. The diameter of the track
cables used was | in. and that of the traction rope, | in. Suitable car-
riers were improvised by using two or more standard tramway timber
carriers. The weight of the material transported by these jigbacks was
approximately as follows : From Control Station No. 3 at the summit,
for Structures Nos. 19, 18, 17, 16, and the towers in Section III, about
60 tons, at a cost of from $2 to $4 per ton, the difference being accounted
for by the fact that the material was unloaded from the line as required :
From Structures Nos. 20 to 15, a distance of 8 300 ft;, 600 tons were
moved, at a cost of $4.20 per ton ; from Structures 15 to 11, 2 600 ft.
distance, 375 tons at $2 per ton; Structures 11 to 9, 4 000 ft., 260 tons
at $3.50 per ton; Structures 9 to 7, 2 700 ft., 210 tons at $2.90 per ton.

The cost per day for the crew required to operate, load, and unload
these temporary cableways was from $35 to $42. The capacity of these
lines, in tons per day, when operating, may be summarized as follows:
From Structures 20 to 15, 13.3 tons; 15 to 11, 33.3 tons; 11 to 9, 23.8
tons; 9 to 7, 29.7 tons. If the capacity is stated in tons per day, includ-
ing the time of putting up, taking down, and moving the jigbacks, the
figures are as follows: Structures 20 to 15, 6.3 tons; 15 to 11, 19.3
tons; 11 to 9, 11.3 tons; 9 to 7, 14 tons.

From Chuckwalla Hollow, between Structures 4 and 5, a line was
built to Control Station No. 1. It cost $35 a day for the crew, and
took 6 days to build. One trip per day could be handled with this line.



722 AERIAL TRAMWAY FOE SALINE VALLEY SALT CO.

at an average cost of $50. If the material was light, such as wood,
water, etc., two trips could be made. This meant a labor cost of more
than $25 per ton for handling motors and other heavy pieces of
machinery from Structures 4 to 7. This expense is accounted for when
it is recalled that the vertical lift is 1 900 ft. in a horizontal distance
of 3 500 ft.

Saline Valley can be reached by a wagon road, approximately 55
miles long, which leaves the railroad at Big Pine. About 375 tons
were hauled over this road at a cost of $35 per ton. All the cables
required between Stations 1 and 2, together with the 75-h.p. motor,
transformers, and heavy station material, were moved from the summit
to a point in Daisy Canyon about 1 500 ft. west of Control Station
No. 2, This material was transported on what is called a "go devil."
This device consisted of a timber frame supported on an axle 8 ft.
long which passed through two heavy wheels. The rear end of the
frame rested on the ground, and was shod with iron in order to pre-
vent excessive wear. On each side of the frame, near the rear end,
steel hooks were arranged, so that two men, one on each side of the
frame, could lift it free from the road when the gradient was light.
On the other hand, these hooks were used to check the velocity of the
device when traveling over ground that was soft enough for them to
penetrate. The operators used both hooks in coming down steep
places, and also assisted the team in steering the device. Fortimately,
no road was required for the operation of this machine, as the canyon
was fairly straight and the bottom free from ledge rock.

The material was moved to Control Station No. 2 on a tramway
constructed with two carrying cables mounting four carriers. A dif-
ferent system was adopted for stringing the cables from the summit to
Control Station No. 2, and also from No. 2 to No. 1. This consisted
of coupling cables together and letting them down the mountain side
by gravity. It was necessary to keep from three to five men at the
leading end so as to put the cables on the traction rope guide sheaves
of the towers and stations. The velocity of the cable was controlled
with 4 by 8-in. blocks bolted together, so that the cable could be squeezed
as it passed along. Each one of these extemporaneous brakes would
resist a pull of about 1 000 lb. until a groove equal to the depth of the
cable was worn in it. When this occurred the clamp was changed so



t ^ r^>>^













YiG. 7. — The 2 400-Ft. Span. Control Station No. 1 is at the Top, Under

THE Cross.



«



Fig. 8. — Tramway Crossing Daisy Canyon, Structures 10 to 11 ; 2 260-Ft. Span ;
600 Feet Above Bottom ; 85% Grade Into Structure 11.



M



AERIAL TRAMWAY FOR SALINE VALLEY SALT CO. 727

that the cable would bear on a new spot. From Structure 4 to Control
Station No. 1 the cables were pulled up with a winch driven by a gaso-
line engine. On Sections lY and V the cables were strung and placed
under tension in the usual manner, except that on Section V the grade
was sufficient to make it desirable to use the gravity method. In plac-
ing the traction rope for Sections III and II, it was threaded around
the grip sheave at the summit station. The grip sheave acted as a
driving sheave, due to the use of a brake on the reel, which imposed
tension in the traction rope before it passed around the grip sheave.
The traction rope was also passed through hauling clamps before
reaching the grip sheave so as to hold it when splices were being made,
or in cases of emergency. After getting the traction rope for one side
to Control Station No. 1, the upper end at Station 20 was snubbed, and
the rope for the opposite side was let down in the same manner. After
the upper ends had been spliced, the ropes were cut at Control Station
No. 2 and passed around the tension and grip sheaves of this station.

The towers and structures are carried on concrete foundations, and
the water required for making the concrete was hauled in tanks or
packed by mules for distances ranging from 1 to 7 miles. This was
also true for the water required for the camps, except those at the rail-
road, in Daisy Canyon, and Saline Valley. All permanent camps on
the east slope were at elevations lower than 6 000 ft., and those on the
west slope lower than 7 500 ft., so as to be below the usual snow
line. As the mountains are extremely barren, firewood had to be
hauled or packed to the camps from the most convenient points, and
these were often at considerable distances.

From October 1st to April snow storms are of frequent occurrence,
and, owing to the steepness of the hillsides, constitute a menace to
construction at all altitudes above 6 500 ft. In the spring occasional
slides have occurred on the eastern slope, and have proved disastrous
to the construction crews. The drifting snow was very objectionable,
owing to the difficulty of keeping the trails open. Due to these several
causes, the work was arranged so that it could be performed at eleva-
tions below the snow line during the winter.

The erection of the line was pushed energetically, and the tramw;ay
was ready for the preliminary test on June 10th, but the electrical con-



728 AEEIAL TRAMWAY FOR SALINE VALLEY SALT CO.

nections from the power-house of the Los Angeles Aqueduct, which is
in Cottonwood Canyon on the opposite side of Owens Lake, were not
completed until later. The first bucket of salt arrived at the discharge
terminal on July 2d, 1913, and was the occasion for a great
demonstration.

The placing of salt at the railroad was a great achievement, and
taxed to the utmost the financial capacity of the Saline Valley Salt
Company. The reasons for this stringency may be indicated as follows :
After the contract was signed, the question of the location of the dis-
charge terminal was an open one for the next 7 months. This inde-
cision as to the terminus of the tramway affected the schedule which
was prepared to guide the manufacturer in fabricating and shipping
essential parts. It also deranged the plans of the construction crew.
Nothing could be done in the making of surveys and the preparation
of profiles, designs, or drawings until the site of the discharge terminal
was known. Because of this confusion the completion of the contract
was delayed beyond the intended date, so that the Salt Company was
required to meet the expenses of a construction organization for a
longer period than was contemplated in the original estimates.

The contract specified that the capabilities of the tramway should
be demonstrated by an operating test of not more than 60 days, under
the supervision of the engineers of the buyer and seller. To carry out
this provision, active steps were taken by the field engineers to place
the specified number of carriers on the line and to co-ordinate the
various functions of the machinery, carriers, and signal systems so
that the operating test could be undertaken as speedily as possible.

The line worked with great satisfaction when the buckets were
loaded about two-thirds fidl. When efforts were made to carry full
buckets, it was noted that the number of accidents due to runaway
carriers and others slipping on the traction rope was excessive. An
examination of the equipment was immediately started to ascertain
the cause. After carefully canvassing all the agencies which might
have influenced this unusual behavior of the carriers, the question of
the weight of the salt as furnished to the tramway was raised, and an
investigation was undertaken to determine the facts. The contract
called for the transportation of salt weighing 60 lb. per cu. ft. The



s ^




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Fig. 13. — Bucket of Salt at Loading Terminal.



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^


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..m^^




1^^


|i


■L -''x-


'.x




."^^M


^^


,v




^^H


^.^*l1


\ . . "^ti


7







^^^

1^;^:^^^^


i|


^1


^H



Fig. 14. — Flexible Hoods Connecting Track Cable and Double-Headed
Tramway Rail.



AERIAL TRAMWAY FOR SALINE VALLEY SALT CO. 733

actual weights of the salt, as determined by careful tests at the salt
field, were as follows :

Air-dried salt 60 lb. per cu. ft.

Damp salt 65 " " "

Salt sixfficiently moist to agglomerate when

squeezed in the hand 68.5 '* " "

Salt when brine is dripping slowly 83.3 " " ''

Salt when brine is dripping freely 90.2 " " "

, When brine is running from salt 94.2 " " "

It was also noted that the average run of salt from the field was of
the wet variety, so that its weight was in excess of 80 lb. per cu. ft.
As the weight of saturated salt exceeds by more than 50% the figure
stated in the contract, it is evident that the stresses imposed on the
tramway had a similar range in value. Unfortunately, they were incre-
ments to the stresses contemplated in the original plan. The use of
liberal factors of safety in design is again justified, for otherwise this
line would have failed under the increased burden imposed. When
these conditions were discovered, careful observation of the behavior
of the carrier showed that, when carrying dry salt, they traversed the
line from the loading to the discharge terminals without noticeable
difficulty, but when loaded with wet salt, a few of the buckets would
slip on the traction rope. The points where this difficulty was par-
ticularly pronounced were between Structures 5 and 6 of Section I;
and between Structures 10 and 11 of Section II. There the track
cables are as steep as, or steeper than, can be found on any operating
aerial tramway using friction grips. In order to indicate the excessive
gradients which confronted the designers of this tramway. Table 1 is
presented. All gradients of less than 30% have been omitted. This
table shows the station numbers of the approved survey, the numbers
of the structures, the slope and length of the chord of the span, the
number of loaded carriers supported on the span, and the slope, in
angular measure and in percentage. These data will be found of
great interest, especially to engineers concerned in aerial tramway
design. Those who study Table 1 will realize the difficult problems
these grades imposed on the designers of the tramway.

To know that this aerial structure is in successful operation is a
source of deep gratification to its sponsors. The first great departure



r34



AERIAL TRAMWAY FOR SALINE VALLEY SALT CO.



TABLE 1. — Elements of the Aerial Tramway of the
Saline Valley Salt Company.



Span.



From



To



Slope of
cbord.



Length of chord,
in feet.



No
buckets



span.



Slope of
cable.



Per-
centage
of slope.



Saline to Summit.



135 -H 50 (4)


158 -1- 50 (5)


20*06'


2 450


5


39°20'


81.95


158 - 90 (4)
162 - 48


162 - 48


30°53'




1


36° 17'


73.41


164 - 38


31040'




1


36028'


73.9


164 -1- 38


166 - 68 (6)


32"'16'


Entering No. 6


1


39045'


83.17


168 + 89 (6)


173.


30°27'


709


2


37°49'


77.61


178.


176-


-03 (71


31°51'


Entering No. 7


1


39036'


82.73


178-1-57.3(7)
191 + 34 (8)


191-


-07.7i8)


20°18'


1 335


3


34''30'


68.73


203 H


h48 (9)


18°19'


1 280


3


33°15'


65.5


219 T.


223-


-08 (10)


15°42'


500


1


20037'


37.62


223-1-28 (10)


244-


-10 (11)


22''32'


2 260


5


40°27'


85.25


244-1-63 (11)


247-


-22 (12 1


11°33'




1


19°08'


34.69


251 -f- 31 (13)


265-


-91 (14)


6°18'


i 459


2


21°24'


39.19


271-1-10 (15)


284-


-50T.


15044'


1 892


2


28°11'


53.58


284 -1- 50 T.


289-1- 11 (16)


23°07'


500


1


31°00'


60.0


289 -f 41 (16)


295 -f 31 (17)


17''26'


513.5


1


25023'


47.45


301 -


- 30 T,


310 - 35T.


1303O'


931


2


22036'


41.62


310-


-35T.


318 - 50T.


20°58'


873


2


29036'


56.8


318-


-50T.


320 — 70 T.


24-25'




1


29°20'


56.19


820-


-70T.


322 -f 94 (18)


24°32'




1


31035'


61.5


323 -f 33 (18)


325 -f 30 T.


2O0O6'




1


24057'


46.52


325 -1- 30 T.


330 4- 00 T.


21°18'


508


1


270O6'


51.17


330 4- 00 T.


336 -1- 00 T.


23054'


656


2


30°58'


60.0


336 + 00 T.


838 + 29 (19)


26=06'




1


33°30'


66.19


339 -f 02


351 -h 95


16042'


1 352




31013'


60.6



Summit to


Discharge Terminal.










374 -f- 46 (21)


377 -1- 20 T.


I8031'






26O10'


49.1


377 -1- 20 T.


379 -1- 00 T.


18°33'






23-20'


48.1


379 T.


390 -1- 00 T.


12°31'


1 127




23001'


42.5


896-1-15 (22)


399 -t- 90 T


I9011'






26044'


50.3


399 -f- 90 T.


400 -1- 90 T.


17014'






21045'


89.9


400 + 90 T.


413-1- 50 T.


10°46'


1 285




22^37'


41.6


421 -t- 51 (23)


423 4 70 T.


20°49'






25»44'


48.2


428 -1- 70 T.


426-1-91 (24)


19048'






25*05'


46.8


427-1-13 (24)


448-1-20 (25)


8O10'


2 128




26041'


50.3


497 4-40 (28)


503 T.


I903O'


594




28023'


54.0


503 -r.


504 — SOT.


17°45'






22*26'


41.8


504 -1- 50 T.


506 — 30 T.


17°54'






22-41'


41.8


506 - 30T.


517 - 40T.


12O06'


1 135




22-45'


41.9


551 - 75 (29)


553 -1- 10 (30)


16029'






23014'


42.9


558 - 26 (30)
656 - 50 T.


556 4- 50 T.

557 -f 50 T.


19027'






27051'


52.8


19=08'






23-39'


43.8


557 -1- 50 T.


558 4- 50 T.


19057'






24-28'


45.5


558 -f 50 T.


561 4-34 (31)


20O12'






25021'


47.4


561 -1-57 (31)


580-1-68 (32)


10°33'


1 945




29°26'


56.4


581 -f 46 (82)


584 T.


15035'






22*45'


41.9


584 T.


588 4- 10 T.


I40I8'






19' 53'


36.2


588 -1- 10 T.


590 T.


13019'






18°08'


32.75


590 T.


591 4- 28 T.


13-21'






17058'


32.4


591 -1- 28 T.

592 4- 50 T.


592 4- 50 T.


13°35'






I801O'


32.8


593 4- 77 T.


14-02'






I8038'


83.7


593 + 77 T.


595 T.


14°37'






19012'


34.8


595 T.


597 4- 50 T.


14-50'






19-42'


35.8


597 f 50 T.


600 T.


14°37'






18-39'


83.8


600 T.


605 -^- 80


11-44'






18-19'


38.1


631-1-88 (34)


633 4- 20 T.


22032'






28017'


53.8


633 4- 20 T.


637 4- 30 T.


21-34'






27-09'


51.3


687 + 30 T.


638 4-95 (35)


20-53'






25-37'


47.95


639-1-30 (35)


659-1-26 (36)


9-27'







28-23'


54.0


663 -|- 97 (37)
667 -f 76 (38)


867 -1- 21 (38)


13°11'






20-35'


87.55


675 4- 40 T.


19005'




2


27-58'


53.1


675 -f- 40 T.


680 + 90 T.


I80O8'





2


19-30'


35.4



AERIAL TRAMWAY FOR SALINE VALLEY SALT CO.



735



from standard tramway practice was made when the extreme difference
in elevation between the loading terminal station and the summit was
divided into three sections, and when two sections were used for the
descent from the summit to the discharge station. Experience has
shown that it is not economical to attempt to utilize traction ropes of
large diameter. The total stress developed in such ropes when lifting
20 tons of material IJ miles vertically at the rate of 500 ft. per min.
is so great as to prohibit the use of a single rope for this duty. Mul-
tiple traction ropes, arranged in parallel, are not to be considered when
a more satisfactory solution of the problem can be developed. Accord-
ingly, it was decided that the tramway should be arranged in sections
so as to maintain a traction rope of moderate diameter, and to arrange




ft "" ft "" ft-flo- I




CURVED RAIL STRUCTURE. STATION 23

AERIALTRAMWAY

SALINE VALLEY SALT COMPANY

Fig. 15.
the stations so that there would be a constant difference in their suc-
cessive elevations. It is readily seen that this constant difference in
elevation imposes practically the same stresses on the traction ropes of
each section. The only feature that is not constant is the friction
developed by the moving carriages on those sections which are not of
equal length and, consequently, do not support the same number of
carriers.

Unfortunately, experience has shown that, irrespective of the con-
stancy of tension in two traction ropes in service, they do not maintain
precisely the same diameter. Accordingly, friction grips which have
been designed so as to maintain a uniform closure when adjusted to
hold satisfactorily on the larger of the traction ropes will slip, all other
conditions being constant, when attached to the second traction rope.



736 AERIAL TRAMWAY FOR SALINE VALLEY SALT CO.

By this criterion it was necessary to abandon consideration of the well-
known Webber grip for this service. The use of either the Bleichert
overhead or underhung automatic grips was taken under advisement.
The screw grip, such as Pohlig uses, was unsatisfactory because of the
acceleration required to close the gripping lever, which moves in a
plane parallel with the direction of motion; also because of the great
dijKculty in maintaining a proper limit for the throw of the closing
lever when operating on ropes of different diameters so as to engage
the detacher properly instead of under-running it, an accident which
happens frequently on multiple-section lines where this grip is used.
The overhead grip was eliminated from further consideration because
the extreme tension of the traction rope in passing through structures
on the crests promoted the overturning tendency of the carriers,
especially those on the empty side. The underhung Bleichert grip was
not used on account of the serious doubts entertained concerning its
holding powers on grades as steep as 86 per cent. This grip is operated
by the weight of the load acting on the movable jaw. On steep gradi-
ents the gripping power is materially reduced. The high price of the
grip and carriage of this type, as compared with others, was also a
considerable factor when it is recalled that 286 carriers were needed
for the equipment of the line. As all the accredited grips then known
were found to be unfit for this service, it was decided that a new grip
should be designed so as to hold carriers supporting 12-cu. ft. buckets
loaded with salt weighing 60 lb. per cu. ft. It was also decided that
these grips should be of the trunnion type, so that the loads would hang
vertically on all slopes; that the grips would compensate successfully
without material loss of tractive effort for the different diameters of
traction ropes found on the line; that the grips should be of the under-
hung, top-opening type; and that they should be of moderate cost.

When these grips were furnished and the line was operated, it was
found that they fulfilled most of the aims of the design, but, owing to
the great variation in the weight of the salt and the consequent increase
in drag on the grip, some of them failed by slipping on the extreme
slopes. In other words, the requirement for the constant adjustment
of grips was too great a hazard to success to comply with the severe
specifications imposed by the engineers of the American Steel and
Wire Company, who ruled that, because of their uncertain performance
when handling the heaviest loads possible, they must be replaced. This



AEEIAL TRAMWAY FOE SALINE VALLEY SALT CO. 737

conclusion was reached only after a considerable lapse of time from
the date of arrival of the first bucket of salt at the discharge terminal,
the reason being that the Salt Company experienced grave financial
difficulties which, for about 2 years, prevented running the tramway
in accordance with the contract.

Finally, the American Steel and Wire Company voluntarily took
over the operation of the line at its own expense, so as to determine
what defects, if any, existed, and what replacements should be made.
As a result of this investigation, a new grip, called the Universal Wico,
was perfected, which has demonstrated its fitness for the duty required.
It is designed in strict accordance with the specifications previously
outlined, and has sufficient gripping power on the traction rope to
handle safely on the steepest grades a carrier loaded to its utmost
capacity with the heaviest salt plus the weight of a line rider. It has



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