Chapter XXIV
Culebra Cut
The engineers at Panama have been able
figuratively to wed the oceans only by literally divorcing the mountains. From the
Arctic to the Antarctic there stretches a vast and lofty mountain chain, dividing the East
from the West on two continents. The task that confronted the American engineers was
that of cutting through the weakest of the links of this chain of mountains. When it
was proposed to build the Panama Canal there were those who believed it possible to cut
down the backbone of the Cordilleras until the waters of the oceans could sweep through
unhindered to a depth which even at low tide would carry the largest steamship
afloat. There were others who held that a more feasible plan would be to lift up the
waters, so that they could meet and mingle, not above the mountain tops, but at least a
part of the way above the sea. The latter idea prevailed, and to the fact that it
did prevail the American people owe their triumph at Panama.
In all the world of work there is perhaps no better example of the wisdom of the Infinite
in withholding from man a knowledge of the future; for if the American people had known of
the tremendous difficulties that lay before them in their work of severing the link that
united two continental mountain systems into one chain, it is doubtful if that work would
ever have been undertaken. If some prophet, speaking with foreknowledge, and not
without honor in his own country, had come to the Congress of the United States in 1902,
stating to that body that it would cost $10,000,000 a mile to dig Culebra Cut at its
present level, and that it would require the excavation of over 100,000,000 cubic yards of
material, there would have been no Culebra Cut and no Panama Canal today.
There now stretches through the backbone of the intercontinental divide a canyon cut by
human beings, the only one on the earth. Nine miles long, with an average depth of
120 feet, with a bottom width of 300 feet, and with a top width which reaches at places to
a third of a mile, this marvelous canyon presents at once an inspiring and awesome aspect,
revealing both man's audacity and nature's grim resistance to his efforts. On either
side of the gorge rises a majestic peak, standing as sentinels guarding the passage from
the Atlantic to the Pacific. But now, where once they were bound together with
chains of primeval rock, they are separated by the arm of a lake, the largest yet created
by human cunning. Where once the Chagres river encountered immense barriers which
turned it about and forced it to flow into the Atlantic, now it comes down into that wide
lake, whose waters may be made to flow either into the Atlantic or the Pacific, at the
touch of a button.
To accomplish this wonderful work, the American canal army was called upon to go to
lengths unprecedented in the history of engineering. A thousand and one unforeseen
difficulties arose. Nature interposed her powerful self between the can engineer and
his purpose, and seemed to take almost fiendish delight in a defensive warfare against his
labors. She maneuvered her forces with consummate cunning, in a way best designed to
strike terror to the hearts of those against whom she was defending that mountain pass.
Now she sent down slides which threatened to disrupt the whole system of excavation
in the cut; now these slides became quiescent, as if to lull the engineer into a false
security; now they made a feint, threatening dire results, but stopping short of actual
conflict; now they came in the dead of night, spreading chaos in every direction; now they
seemed to raise the white flag of surrender, allowing the dikes of basalt to peep out as a
message to the engineers that the slides could move no further because they were tied by
these dikes to the very core of the earth; and then they would destroy the hopes which
these dikes aroused by shearing them off as if they were but pipe stems, and flowing,
unrestrained, into the cut.
But through all their trials and tribulations, through all their delays and repulses, the
canal engineers led their forces onward, checking the slides and retrieving every inch of
lost ground, until Nature herself lay exhausted at their feet and accorded them the
triumph for which they had struggled so long and so persistently.
As we look back over the story of Culebra cut we are struck by the constantly rising limit
of the amount of material to be excavated. A few months before Colonel Goethals took
charge at Panama, the amount of material which it was thought would have to be removed was
less than 54,000,000 cubic yards. As we survey the completed project we find that
there has been removed more than 100,000,000 cubic yards; that the cut has been dug at an
outlay of nearly $10,000,000 a mile, and that the heaviest miles have cost as much as
$15,000,000; that the slides added some 30,000,000 cubic yards of material, to say nothing
of the unforeseen difficulties which they brought into the cut with them. We find
that there has been taken out almost as much material to make a lock level cut as was
estimated for the sea-level cut. We find that there was taken out of Culebra Cut to
bring it to the stage of completion as much material as it was estimated would have to be
removed to complete the canal from the Atlantic to the Pacific.
Whether the cut was viewed from the hills above, or from the bottom of the ditch below, it
presented, during the construction period, a strange admixture of awesome proportions and
apparently chaotic conditions; but what seemed to be chaos and confusion was in fact order
and system. Hundreds of well drills, tripod drills, and hand drills ate their way
down through the rock, preparing the holes in which were to be planted the tons of
dynamite used to provide the daily spoil for the forth-odd steam shovels that consumed the
vitals of the cut. Dozens of dirt trains moved to and fro, as they took the spoil
from the shovels and carried it to the dumps, which were an average of some twelve miles
distant. Necessarily there was order and system when the daily stint was that of
loading and hauling away 160 trainloads of material from a cut nine miles long.
The work moved forward at a pace unprecedented in the annals of engineering. In the
nine-mile section in a single twelve-months there was removed a total of 16,386,000 cubic
yards of material. six thousand men labored within this short stretch, preparing for
the blasts, handling shovels and the dirt trains, and shifting the tracks as the work
moved forward. At eleven o'clock in the forenoon and at five in the afternoon the
cut was temporarily deserted; and then there came the thunderous blasts that tore loose
the rock and provided the next four hours' supply of food for the steam shovels.
Dynamite was used in enormous quantities. No mind can conceive of the tremendous
force of 60,000,000 pounds of high powdered dynamite, the amount used by the engineers in
tearing asunder Gold Hill from Contractor's Hill. Were the holes that were drilled
in preparing for the work of the dynamite put end to end, they would more than reach
through the earth itself, at the equator. Great batteries of the largest well
drills, lined up in rows, drove down through the solid rock, to an average of twenty-four
feet in depth; a whole company of tripod drills hammered their noisy way down into the
adamant; while here and there gangs of negroes, swinging heavy sledges to the rhythm of
some folk lore song, drove the steel hand drills inch by inch into the rock. In the
case of the wells a small amount of dynamite was sent to the bottom and exploded in order
to "spring" the hold. Then hundreds of pounds of explosives were put down
into these wells, tamped home, and connected with wires bearing high power current from
the electric light plants. The turning of a switch made the earth shake and
shattered the embedded rock. More than 600 holes were fired daily. In addition
to these there were small "toe" blasts and may "doby" blasts. The
handling of dynamite is never free from dangers, but the Culebra Cut work was so well
ordered under the rules formulated by the Chief engineer, that only eight men were killed
in the handling of 19,000,000 pounds of explosives. In the early years of the work
blasts were set off by simply dry batteries, but it was found that this frequently
resulted in a failure to explode the charge, with constant danger of premature or
unexpected explosions. The substitution of the other method insured the explosion of
every charge. The largest single blasts at Panama were set off in a series of holes
containing 52,000 pounds of dynamite. The most serious accident that ever occurred
was at Bas Obispo, December 12, 1908, when 44,000 pounds of dynamite exploded prematurely,
at the moment when the last load was being tamped home. Great care had to be
exercised in preventing premature explosions. The action of warm moist air on the
iron pyrites sometimes heated the material, causing a blast to go off while being tamped
home. To overcome this, a stream of water was played into the hole before the
dynamite was put down.
After the blasts had been fired, the steam shovels appeared. Some of them could pick
up eight tons of material at a mouthful and take a new mouthful every three minutes.
One ninety-five-ton Bucyrus shovel handled 543,000 cubic yards of material in one
year. The record for a month was 86,844 cubic yards. The average output per
shovel ran up from 500 yards a day in 1905 to more than double that amount in 1912.
There were forty-three shovels at work at the height of activities in Culebra Cut.
To handle the spoil that could be loaded upon the trains required the services of 140
locomotives and 3,700 cars. In a single year the shovels loaded 1,119,000 carloads
of material, and 75 trains were constantly going in and out of the big ditch. When
work reached the climax there was a train in or out nearly every minute of the working
day.
The bulk of the spoil was hauled away on Lidgerwood flat cars. Each car held about
nineteen cubic yards of spoil, and they were run in twenty-one-car trains. The cars
were boarded upon one side only, and steel sheets were hinged from the floor of one car to
the floor of the one ahead, so as to give, to all intents and purposes, a solid car floor
for the entire length of the train. When a train was loaded, it was pulled out of
the cut and hauled to the dumps. Here a huge plow, reposing on a car that had been
unloaded previously, was attached to the train at one end, while a car carrying a large
steam windlass was attached to the other end. A cable the size of a man's wrist was
stretched from the windlass to the plow. When the train was in position for
unloading, the windlass began to turn, pulling the plow along on the floor of the cars
until they were unloaded. then the car on which the plow finally rested and the one
on which the windlass rested were cut out of the train, and it was hauled back empty.
The heavy cable that pulled the plow over the floor of the train was stretched in an
ingenious way. There was a frame built across the track like those which support the
warning ropes at overhead bridges and tunnels. The train to be unloaded ran through
this frame, switched in the car containing the windlass, and attached the end of the cable
to the frame. As the train moved back, the cable was stretched along the length of
the train and was ready to be attached to the plow as soon as the car carrying it was
attached to the train. All this indicates that there was considerable switching in
placing the cars containing the windlass and the plow into the train and cutting them out
again. There was; but the men who did it became so adept that there was
comparatively little delay.
After the plow had removed the dirt from the cars and the empty train had started back for
another load, another engine came along with another sort of plow. This plow ran
along the track and pushed the dirt down the bank. It was followed, in turn, by a
track shifter, which lifted the track over bodily to the new position that the widened
bank made possible. And thus the work went forward. Every operation that could
be performed by machinery was taken out of the hands of the laborers. Each of these
inventions made it possible for one man to do the work of dozens. Each car gave up
its load in a half minute; the spreader forced a trainload of rock and earth down the bank
in ten minutes; and the track shifters always had the track moved over by the time
the next train was ready to discharge its burden.
From time to time many improvements were made in these different devices. As
originally constructed the floors of the Lidgerwood cars extended the same distance over
the wheels on both sides. This did not permit a proper centering of the load,
necessitating its being placed too much on the boarded side, which resulted in an
excessive wear and tear on the wheels of one side of the car. An apron was therefore
built on the other side of the car, which extended the floor a foot or more over the
wheels. This permitted the load to be centered, and at the same time permitted the
plow to throw the material further away from the track. It also gave the car a
nineteen-yard capacity where it formerly had a sixteen-yard capacity.
The cables at first were likely to break when the plow struck an obstruction, such as a
large stone or a broken car-floor; a weak line, with a braking-point just a little weaker
than that of the cable, overcome the difficulty. Couplers sometimes became worn or
broken under hard usage, causing the parting of a train at times when it was desirable
that such things should not happen; a master mechanic invented a kind of
"bridle" that saved the day here. The plows sometimes caught the edge of
the side board at the end of a car; a bullnose piece of iron was devised, which steered
the plow away from the side boards. Some fifty-odd improvements were made on the
spreaders alone.
In addition to the Lidgerwood equipment for hauling away the spoil, a large number of
Western Dump Cars, dumped by compressed air, and a number of ordinary cars, dumped by
hand, were used. At the height of the work 333 trainloads of material were handled
by the Central Division in a single day, the bulk of them coming from Culebra Cut.
The disposal of the spoil was a serious problem. Over a hundred million cubic yards
of material had to be hauled away and dumped. With a part of it the engineers
converted an island into a peninsula, three and a quarter miles out in the Pacific Ocean.
This peninsula is the Naos Island Breakwater, which serves the double purpose of
providing communication between the mainland the Pacific fortifications, and preventing
the cross currents of Panama Bay from filing up the end of the canal with silt. With
another part of the spoil they converted nearly 500 acres of the Pacific Ocean into a town
site and a military reservation. With still another part of it they made a parade
ground. But still scores of millions of cubic yards of this debris had to be hauled
out and dumped in the jungle. In one of these big waste dumps 17,000,000 cubic yards
of material were disposed of.
The Naos Island Breakwater was the most troublesome work on the isthmus. At one spot
it settled 125 feet. In not a single foot of its more than three miles of length is
the original trestle to be found under the tracks it was meant to support. It sank
down and shifted to the side, at some places as much as 300 feet from the spot where it
was put down.
Disposition of the spoil in the wet season was difficult. Imagine a dump covering
perhaps 1,000 acres, and with tracks over its several terraces. Then picture a
rainfall twice as heavy as that which occurs in the United States, dashing down and
converting this great dump of freshly excavated material into a sea of mud. Then
fancy the dirt trains running though that sea of mud, with the track sinking three or four
feet, and shifting to one side or the other. Then watch the trainmen working and
toiling to extricate their trains. that is what might have been seen hundreds, if
not thousands, of times at Panama. But through it all, and in spite of it all, the
trains kept running and disposing of the spoil, for when the trains stopped, all other
work ceased.
We now come to the slides; and no man who ever saw them working their way into Culebra Cut
can fail to see in them the handwriting on the wall -- the handwriting that says that no
sea-level canal shall ever be built at Panama. Bringing into Culebra Cut more than
250 acres of land, buildings, and all; driving downward 30,000,000 cubic yards of material
which ought never to have come into the cut; imposing upon the canal engineers not only
the task of removing all this extra material, but multiplying the difficulties under which
the material which belonged in the cut was removed, -- the slides were Nature's heavy
artillery, indeed, in repelling the invasion of man.
They were absolutely unforeseen. No one dreamed that material would move into
Culebra Cut in quantities vast enough to load a train of cars reaching half way round the
earth, and requiring the equivalent of a string of locomotives 700 miles long to haul it
away. Nor did nay one foresee that the cut would be choked up repeatedly, now
disrupting one-half of the entire transportation system, now disrupting the other half.
A total of 200 miles of railroad track was covered up, destroyed, or dislocated in
a single year by these slides. The very bottom of the cut itself was upraised
sometimes as much as 18 feet, as if to recover the ground lost by the operation of the
steam shovels and the dirt trains.
It was more than the mere digging of a ditch that Colonel Goethals had to encounter when
seventy-five acres of the town of Culebra broke away and moved foot by foot into the
canal; carrying hotels and club houses with them until these buildings were removed.
Cucaracha slide carried into the cut many millions of cubic yards of material,
bottling up the channel, and sending its "toe" sixty-odd feet up the other side.
It was fight, fight, fight, now with the dynamite, now with the steam shovels, now
with hydraulic excavators, and now with dredges. The campaign finally resolved
itself into one of inviting the slides to do their worst, and then meeting them as they
came. Some of them, like Cucaracha, were mere masses of material slipping by force
of gravity into the channel; others, like West Culebra slide, were breaks. If a cut
is dug deep enough, even side walls of granite finally will break at the bottom, causing
the material above to press down and into the cut. This is what happened at West
Culebra. The material at the bottom broke, and the material above forced its way
down, and like water poured into a U tube, rose up on the other side -- the other side in
this case being the bottom of the canal.
Sometimes these breaks played uncanny tricks. At one place a steam shovel, track and
all, was picked up and carried half way across Culebra Cut, where it was left unharmed.
At another place, where three tracks were close together, the one nearest the bank
sank down several feet, and the one farthest from the bank rose up correspondingly, while
the middle one was not disturbed. One slide kept a gradual motion, moving down just
as fast as the steam shovel worked, so that the shovel was able to make 103 trips across
the "toe" of the slide without shifting its track an inch.
Cucaracha, with its fifty acres or more of sliding material, was first in the field,
having paid the French a visit that drove them from that part of the Culebra Cut.
Again in 1905 it came down, and once more in 1907. Intermittently it has been in
motion ever since. At one time it broke so far back that the rear part sloped away
from the canal. then a hydraulic jet, with a nozzle pressure of eighty pounds to the
inch, was turned on the materials that drained away from the cut, and they were sluiced
back into another valley.
The actual delay in the completion of Culebra Cut because of the slides cannot be
ascertained accurately. If the slides had not involved any other difficulty than
that of removing them the delay would have been twenty-two months. But when we
reckon all the hindrances to the other work, it is probable that the total delay involved
is not less than two and a half years. In other words, but for the slides, Colonel
Goethals and his lieutenants would have completed Culebra Cut by the first of January,
1912; they would have removed the 70,000,000 cubic yards of material, other than the
slides, in five years, although, the board of consulting engineers said it would require
eight years to remove 54,000,000 cubic yards; and they would have removed the larger
amount with forty steam shovels, although the board of consulting engineers estimated that
it would require 100 steam shovels to remove the smaller amount.
The board of consulting engineers, in fact, went astray in dealing with Culebra Cut.
Serious results would have followed the adoption of their recommendations.
They reported that a sea-level Culebra Cut would require the excavation of only
110,000,000 cubic yards of material; it has taken almost that much work to build the
lock-level cut. It would probably require the removal of another 100,000,000 cubic
yards to bring the present cut down to sea level.
Those engineers in the majority report ridiculed the idea of encountering any serious
difficulties o\in Culebra Cut; they said its banks would stand up with an average slope of
three feet rise on two feet back; yet at some places there is only one foot rise to ten
feet back. They said a hundred shovels could be operated in Culebra Cut; the highest
numbered operated was forty-three. They said handling the slides was only a question
of drainage; and yet the worst ones occurred in the dry season.
The American people probably owe it to Mr. Roosevelt that their enterprise at Panama did
not fail as ingloriously as the French project. If he had not possessed the moral
courage to change his own mind, and to come out against such a powerful majority as that
on his board of consulting engineers, the country would be awaking to the discovery that a
sea-level canal is an impossibility -- so far as pocketbooks and patience go -- instead of
putting the finishing touches on the lock canal. Meanwhile there would have been
expended some $50,000,000 in digging a sea-level ditch from Gatun to Gamboa; some
$8,000,000 on a masonry dam at Gamboa, and as much more on tidal locks at Sosa Hill --
only to find that none of these expenditures would have been of value in building a lock
canal.
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from: History of the
Panama Canal
by Ira E. Bennett, 1915
CZBrats
March 24, 1999