THE CULEBRA CUT.
The most famous section of work on the canal has been that at the
vertebra or "continental divide," which runs along the isthmus on the
Pacific side and had to be pierced through by any canal running from
Colon to Panama. This tremendous work, known as the "Culebra Cut," from
the name of one of the hills, extends for nine miles from Bas Obispo to
Pedro Miguel. Mr. Bryce has truly said, referring to this section, that
"never before on our planet have so much labour, so much scientific
knowledge, and so much executive skill been concentrated on a work
designed to bring the nations nearer to one another and serve the
interests of all mankind."[16] The bottom of the canal in the cut, as in
the channel through Lake Gatun, is 40 feet above sea-level. The highest
elevation of the original surface of the ground above the centre line of
the canal was 312 feet above sea-level, so that the total excavation
along this saddle was 312 minus 40, or 272 feet. This was, however, not
actually the highest point of excavation. Gold Hill, close to the canal
line, is 534 feet above sea-level, and from the top of this hill a new
and steeper slope had to be made. The surface of the water is 85 feet
above sea-level, and so is 227 feet below the original saddle at its
highest elevation. We have already noticed that a tide-level canal would
have involved an excavation 85 feet deeper, and the width of the cutting
would have had to be immensely wider. The slides and breaks which have
rendered the American excavation so much more difficult lead one to
suppose that the tide-level cutting might have proved impracticable.
All the work at Culebra performed by the French was available for their
successors. The French companies accounted for 18,646,000 cubic yards of
material on this section. They had already cut down 152 feet below the
original surface at its highest elevation, and the cliff they had cut
in the face of Gold Hill was 374 feet in vertical height. It is well to
mention such figures, as some people imagine that the French wasted all
their time and resources at Panama. It may be added that the bottom
width of the channel adopted by the French engineers was 74 feet,
whereas that of the American canal will be 300 feet.
Many descriptions have been given by visitors of the spectacle presented
in this long and deep gash through the mountains during the progress of
the excavations. From these and the numerous photographs taken at that
stage the traveller will be able to reconstruct the scene--the two
hundred miles of railroad construction track, laid down tier above tier
at different levels; the thousands of men busily at work; the roar and
smoke of the dynamite tearing the rock into fragments; the mighty
steam-shovels like great dragons burying their iron teeth in the surface
of the bank, engulfing a huge mouthful, then swinging round and belching
it all into the dirt trucks, to be carried off to the dumping-ground at
Gatun near the Atlantic or Balboa at the Pacific end of the canal. At
Culebra, Colonel Goethals made the "dirt fly" to the full satisfaction
of public opinion in the United States. All sorts of devices and
machinery were employed to hasten and economize the process. For
example, there was the Ledgerwood Unloader. Railway trucks provided with
flaps were used, these flaps making a single platform of the whole
train. At the rear of the train was a plough which could be drawn by a
wire rope attached to a drum carried on a special car in the fore part
of the train. When the train arrived at the dumping-ground the drum was
started, and the plough, advancing from the rear, swept the 320 cubic
yards and rock from the sixteen cars in seven minutes. Then there was a
"track-shifter," invented by an employee on the isthmus, which lifted
and relaid the railway lines as the spoil-tracks had to be shifted. This
powerful engine raised the track and ties clear of the ground and
deposited them from three to nine feet sideways.
The "spoil trains" were treated with all the respect which is accorded
to the fastest mail trains of the day on an English main line. They
followed one another from the cutting at intervals of three minutes, and
any delay, of course, balked the mammoth steam-shovel of its gluttonous
meal on the stones and rubble of the mountain-side. Any cause of delay
was at once reported by telephone to the superintendent of
transportation at Empire, and the obstruction was immediately dealt
with. By this persistent concentration on the main object the dirt has
been made to fly not only more speedily but more cheaply.
One of the most serious causes of anxiety and difficulty along the canal
line were the "slides" and "breaks" which kept occurring in the Culebra
Cut. To use a condensed Americanism, the sides would not "stay put."
Large masses of material would slide or move from the banks into the
excavated area, closing off the drainage, upsetting the steam-shovels,
and tearing up the tracks. A very unpleasant phenomenon was the lifting
of the shovels in the bottom of the canal due to the bulgings of the
earth there. It is not necessary to enter into the distinction between
"slides" and "breaks," or into the learned disquisitions that have been
written about them. It is sufficient for us to note that they added
immensely to the amount of material which had to be got out of the
Culebra gorge. Colonel Goethals tells us that of the 14,325,876 cubic
yards removed during the year 1909, 884,530 cubic yards, or 6 per cent.,
were due to slides; that in 1910 of 14,921,750 cubic yards removed,
2,649,000, or 18 per cent., came from slides or breaks that had
previously existed or that had developed during the year.
It might have been imagined that these discouraging additions to the
work would have seriously delayed progress on the canal and put forward
the date of its completion. But able and economic organization triumphed
over all these lets and hindrances. At the beginning of the American
excavations the engineers estimated that 103 million cubic yards of
"dirt" had still to be removed, and that this work would take nine years
to accomplish. But that estimate of material proved to be greatly below
the mark. Enlargements of the canal and the unforeseen collapses in the
Culebra Cut brought up the total to 195 million cubic yards. It is a
remarkable evidence of the efficiency and economy of the American
organization that this immense task will have been completed in about
six years of actual full-swing work.
Some idea of the way in which Colonel Goethals made the dirt fly may be
gathered from the fact that in the first five years of his directorship,
down to April 1912, he removed 160 million cubic yards of material. "If
all this material," writes Mr. Showalter, "could be placed in a solid
shaft of the shape of the Washington Monument, with a base as large as
an average city block, it would tower more than six miles skyward,
overtopping the earth's loftiest mountain peak by more than a mile.
Again, if it were to be loaded on to the big Lidgerwood dirt cars used
on the canal, it would make a string of them reaching over two and a
half times around the earth, and requiring a string of engines reaching
from New York to Sac Francisco to move them." It is indeed a remarkable
achievement that, while the amount of material to be removed was
increased by about 90 per cent., the time of removal was cut down by 30
per cent. Nor has the increase of the work added to the estimate of
cost. The total cost of the completed canal was fixed in 1908 at 375
million dollars. Yet, in spite of the increased excavations, enough of
this sum, it is calculated, will be left over to build a new
breakwater, and perhaps a big storage reservoir at Alhajuela on the
upper reaches of the Chagres River. In the Culebra Cut, despite the
landslides, the cost of excavation has actually been reduced by more
than one-third.
[Illustration: Culebra Cut, from West Bank, showing Shovels at Work.]
The pessimists have of course been busy with these landslides in the
"Cut." They predicted that the canal along this section would always be
exposed to danger from that source. But here, too, every precaution has
been taken. The engineers have given a much lower slope to the sides of
the canal, which is therefore wider at the top than had been originally
planned. The slopes will also be sown with creeping grasses and other
plants, which will bind down the surface soil. When the forty-five feet
of water are in the canal, the bottom will be held down by the weight,
and the bulgings no longer take place. Moreover, any earth that, in
spite of all precautions, still manages to slide into the canal should
be easily dealt with by the big 20-inch suction dredges, which can be
brought up through the locks and set to work. So we need not trouble
much about the stability of things along this nine-mile section through
the Culebra Mountains.
Here as elsewhere it is possible to give only a very general idea of the
difficulties which were encountered and overcome in the course of
construction. The drainage of the "Cut" during the work was in itself a
heavy and important task. It was necessary to keep out the water of the
surrounding country and to rid the excavated area of water collecting in
it. A system of diversion channels, carrying off the Obispo River and
its tributaries, effected the first object, and the second problem was
solved by gravity drains and pumps. On the whole, this mighty trench
through the isthmian hills is not only the biggest thing to the credit
of a nation which delights in bigness, but the greatest achievement of
its kind the world has ever seen.
FOOTNOTES:
[16] "South America," p. 26.