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