Chapter LII
American Industries And The Canal
Strongly as the Panama Canal appeals to the imagination as the carrying out of an ideal,
it is above all things a practical, mechanical, and industrial achievement. the
completed work is made up of a multitude of industrial efforts applied to every phase of
the actual work of construction, the machinery used on the canal, and to the health and
comfort of the men engaged in the work
From the gigantic dredges, cranes, and other appliances designed especially for the construction of the canal to the use of bronze instead of iron in delicate machinery to offset the rust conditions of a tropical climate, the practical genius of the American industrial world rose to meet the new and extraordinary conditions under which the work progressed to a triumphant conclusion.
It is a matter of pride to the United States that although the competitive system of bidding was in vogue on the canal, American machinery, American sanitary appliances and American goods of all descriptions were almost without exception found the best and most economical. There was o graft and no waste in the canal work. The products of industry, both the myriad implements and for the men who labored on the canal, were the best the world could provide.
It may well be that the construction of the Panama Canal will remain for centuries the most stupendous engineering and practical feat of man. For this reason, it was deemed wise to incorporate in this history an outline of the machinery and industrial products and appliances which were used on the canal, not only as a matter of present pride and satisfaction, but because this phase will be of extreme historical value to the student in future years. Even in the short period of time between the cessation of work on the canal by the French and the beginning of the American operations, a remarkable development in machinery and construction equipment had occurred.
The French railways, engines, dredges, hoists, steam shovels and practically all other equipment had become far out of date. The little Belgian locomotives, resurrected from their rust and decay, testified to the good workmanship of their makers by getting into action in the beginning of the American operations, and some of the remaining French machinery was used for a time, but only pending the arrival at the Canal Zone of the more modern equipment which had come into being since the French operations ceased.
In the period following the failure of the de Lesseps plan until the United States began the construction of the canal, the era of steel and machinery development had attained full growth in America. The sky-scraper building had come into being, with its attendant construction machinery. Plentiful supplies of oil and gasoline as fuel had resulted in new types of engines. The great development of American railroads had brought forth heavier engines, and in their path a multitude of machines for excavating, bridge construction, grading, and expeditious shifting or leading of freight. The use of concrete had increased sevenfold, together with the machinery necessary to its use. The giant dredges of the western gold fields, the swamp lands, and the rivers and harbors of the country had been perfected.
When the American engineers came to the building of the canal, all the fruits of this development were ready to aid them. Based on practical experience at home, there was no problem at the canal which American inventive and constructive genius was not ready to solve. If the canal engineers wanted larger machines, the manufacturer was ready to make them. If some types of machinery or equipment staggered under the continuous strain of the canal drive, the manufacturers knew how to strengthen them. They were always ready to fill all requisitions promptly and efficiently. Beyond question, the early completion of the canal is greatly due to the hearty spirit with which American manufacturers cooperated with the desire of the canal builders for speed and efficiency.
Just as the French equipment passed into an obsolete day, so with another turn of Time's wheel, the great engines and machinery which completed the cut from ocean to ocean may take their place on the crap heap; but at present they embody the high mark of mechanical efficiency in the world, with a record that is well worth the attention of the present generation and that of posterity.
Second only to the roll of honor of men who had part in the actual construction of the canal is the roll of American industrial concerns which had so great a part in making the labor of the men more healthful, more expeditious, and less arduous. The canal's "Industrial Roll of Honor" is worthy of a high place in the pride which all the world must take in the culmination of the dream of centuries—the linking of the two oceans by those who work as well as dream.
The various industrial elements which made up the completed canal drop easily into several great divisions. The chief of these are the application of electricity to the completed work and during construction; the efficient drilling machinery which paved the way for the enormous quantity of explosives; the processes of blasting; the part which wire roping played in canal construction; the great steam shovels; the crushing, dredging, and excavating machinery; the sanitary equipment; the enormous consumption of cement; the mechanism of transportation; and the vast amount of miscellaneous equipment which American Industry provided.
Electricity In The Construction And Operation Of The Canal
In describing the utilization of electric energy in the construction and operation of the Panama Canal, a comprehensive idea of the character of the apparatus provided may be most logically obtained by segregating the references under three general heads:
The first comprises the equipment of the power stations, both steam and hydraulic, in which the necessary energy s generated, and the transmission system by means of which it is distributed to the various working points.
The second includes the motor and control equipment of dredges, cableways, loading and unloading devices, electric locomotive haulage, and the operation of auxiliaries, such as rock crushers, cement mixers, etc., required during the construction period.
The third section deals with the part played by the electric motor in the operation of the lock machinery, the devices designed to ensure safety, coordination and positive control of the various sections during the cycle of operations involved in passing a ship through the locks, and the unique type of haulage locomotives adopted for handling the ships during their transfer to different levels.
In providing electrical equipment for the Canal Zone, it was necessary to consider the special nature of the operating conditions imposed by climate, the imperative demand for continuous service in spite of the apparatus being so far away from the manufacturer of electrical supplies, and the importance of having all parts as nearly "fool proof" as possible. All this entailed a great deal of study and care on the part of the Isthmian Canal Commission engineers in preparing the specifications, and on the part of the manufacturer in building the apparatus to meet these conditions.
The power distribution is composed of:
A 2,200-volt hydro-electric power plant at the Gatun dam spillway.
A steam-electric power plant at Miraflores, erected originally to supply power for construction work, but which will be held for emergency operation.
A double 44,000-volt transmission line across the isthmus, connecting Cristobal and Balboa with the two power plants.
Four 44,000/2,200/240 volt sub-stations, stepping down at Cristobal and Balboa, and up or down at Gatun and Miraflores, depending upon which one of the two plants supplies the power.
Thirty-six 2200/240 volt transmission stations for power, traction, and light at the Gatun, Pedro Miguel, and Miraflores locks.
Three 2200/220/110 volt transformer stations for the index and control boards at the three locks.
Similar stations at Cristobal and Balboa for coal handling plants, machine shops, and dry docks.
The Gatun hydro-electric station is located at the dam of the artificial Gatun Lake, so that the water from the wheels, together with that from the spillways discharges into the original channel of the Chagres River. The present installation consists of three 2,000 kw., 2,200 volt, 25 cycle, three phase alternators direct connected to 250 r.p.m. vertical reaction-type water-wheels provided with direct connected exciters, as well as two induction motor-driven exciters with a generator voltage regulator. The station plans anticipate the possibility of three additional generators, should the Panama Railroad be electrified and its traffic be increased to require that amount of power. All switches for the control of machines and a 2,200 volt feeders are electrically operated (including rheostats, exciters, and field switches) by a storage battery, which also provides emergency lighting for the station through automatic transfer switches in case of failure of the alternating current lighting source.
Current is transmitted at the generator voltage to the principal sub-station, also located at Gatun, through which it passes after transformation to 44,000 volts, to the main duplicate transmission line running entirely across the isthmus, and inter-connecting the various sub-stations.
These two three-phase transmission lines consist of No. 00 copper cables with ground conductors of the same size and material, all supported by steel towers placed on both sides of the re-located Panama Railroad. the duplicate steel towers on each side of the railroad are tied together by skeleton steel bridges, some twenty-four feet above the tracks, from which catenary trolleys may easily be suspended should the railroad be electrified.
The four sub-stations are almost identical in size and equipment, although the number of 2,200 volt feeders is somewhat different. The Cristobal and Balboa stations have only outgoing feeders, as they are distributing stations for power to coal handling plants, dry docks, machine shops, etc., where the current is again transformed from the 2,200 volts to the most suitable voltage for the local conditions. The Gatun and Miraflores stations both receive and distribute 2,200 volt current. As already stated, the Gatun sub-station normally feeds the entire transmission system from the hydro-electric plant; and from the 2,200 volt busses in this sub-station the current for operating the Gatun locks is also distributed. The Miraflores sub-station is similarly arranged in order that it may, under emergency conditions, feed the transmission system from the steam-electric plant, and also supply the current for operating the Miraflores and Pedro Miguel locks.
During the construction period electric energy was supplied by two Curtis steam turbo-generator plants, one at Miraflores, which was later held as a reserve station, and a second at Gatun; each having an output of 4,500 kw.
Steam power was generally used in connection with the hydraulic dredging, although in a number of instances centrifugal suction pumps were driven by electric motors. For the construction of the large dam at Gatun several such pumps were used driven by three-phase induction motors.
The greatest field for electric power application in the construction of the Panama was in connection with the building of the different locks. the amount of concrete required for this work was over five million cubic yards, and it was in the manufacturing and placing of this vast amount that electricity played an important part.
On the Atlantic division the crushed rock was received from the quarries and crushers located at Porto Bello, about twenty miles east of Colon, from whence it was transported by means of barges to the storage point at Gatun. The sand was also transported by means of barges from the sand pits at Nombre de Dios, about fifteen miles beyond Porto Bello. The rock crushing machinery at Porto Bello was operated by steam engines.
The rock and sand were unloaded and stored at Gatun by means of three cableways, two of which were the duplex type. These cableways were operated by 500 volt direct current motors; separate motors being provided for driving the cableways along the track and for the hoisting and conveying drums. All the cement was shipped by boat from New York, and the transfer from the barges to the cement shed was effected by ten electrically operated traveling cranes. From the cement shed and the stock piles the raw material was transported to the concrete mixing plant by a three-phase automatic railway.
The concrete mixing plant at Gatun consisted of eight electrically operated mixers, each having a capacity of about 2 1/2 cubic yards. From this plant the concrete was hauled to the lock sites on a third-rail, 550 volt, direct current industrial railway by means of thirteen 6 1/2-ton locomotives. Four duplicate cableways spanned the site of the locks of this concrete railway and transported the dump-buckets to any required point in the lock structure. The complete operation of the towers was done by direct current motors, and the cableways were operated continuously day and night, the lighting at night being effected by searchlights.
For the Miraflores and Pedro Miguel locks on the Pacific division the method of construction was different from that at the Gatun locks. The rock was, in this case, obtained close to the lock site, from the Ancon Hill, where a number of electrically operated crushers were located, the crushed rock being carried from the crushers to the mixing plant by means of conveyors. the sand was transported in barges from Chame Point, twenty miles from the west entrance of the canal. At the docks in Balboa it was unloaded by high speed electrically operated cranes, and transported by rail to the storage yards which were located close to the mixing plants.
Several of these electrically operate concrete mixing plants located in the towers of the cranes were provided; the sand and rock being obtained from the storage piles nearby, while the cement was transported from the Atlantic side by rail.
For removing and placing the concrete forms and for laying the concrete, four berm cranes and four chamber cranes were provided, the chamber cranes operating on tracks in the lock chambers. The berm cranes were used only at Miraflores. They consisted of metal towers, with fixed cantilevers on one side, operating over storage piles parallel to the lock site, and with booms on the other side. The material was transferred to the concrete mixers located in the towers, and the concrete handled by the booms to the side walls, or the batches transferred to the chamber cranes and laid in the central wall.
At Pedro Miguel the berm cranes could not be operated in the same way, and were therefore, modified, in that fixed cantilevers were provided on either side of the towers.
The mixed concrete was hauled from the mixers on the towers to the lock pit by cars, and thereafter placed in the central and side walls by the chamber cranes. These cranes were all electrically operated, the motors being of the 500 volt, direct current type.
The magnitude of the work involved called for the design and construction of special machinery, and the ease with which motor drive met the most extreme demands in fluctuating loads, and the operation of conveying apparatus carrying unusual weights at unprecedented speeds, constitute a striking example of the flexibility and overall efficiency of electric drive, which became an important factor in securing the excellent operating records which characterized this work.
Electrical Operation
Approximately 1,500 electric motors have been permanently installed for the complete operation of the canal. All of the motors provided for the gates, valves, machinery, dams and cranes are of very substantial construction, being similar to those adopted for heavy duty work in steel rolling mills. They are provided with solenoid brakes and are specially insulted to withstand deterioration due to climatic conditions. The motors are operated on 240 volt, three-phase, 25 cycle circuits.
The rising stem gate valves provided for the main culverts in the side and center wall of the locks, and through which the water from the upper valves will be admitted to the lock chambers, are operated by 116 40 H.P. motors. the upper end of the valve stem is carried by a cross-head actuated by two vertical revolving non-rising screws driven by a reducing gear from a horizontal shaft direct coupled to the driving motor. By means of the solenoid brake the revolving parts may be brought rapidly to rest and, while the machinery is normally operated through a remote control system, auxiliary hand apparatus has been provided for closing the gate in the event of failure of the machinery when it is in the raised position.
At the various locks there are a total of 120 cylindrical valves, each of which is operated by a 7 H.P. motor, the function of these being to control the flow of water from the center wall culvert into the lateral culverts beneath the floor of the lock chamber.
For the operation of the forty-six pairs of locks gates, ninety-two 25 H.P. motors have been provided, one for each gate leaf. In addition to these there are forty-six 7. H.P. motors for operating the miter forcing machines, which force the gate leaves to a perfect junction and lock them in the mitered position. Eighteen 25 H.P. motors are used for operating the guard valve machines which operate the valves that guard the intakes of the side wall culverts at the upper end of each flight of locks.
The hand-rail motors are required to furnish the power for raising and lowering the hand-rails of the footwalk across the tops of the miter gates. These walks provide a passageway for crossing the locks when the gates are closed, and the hand-rail guards the passage. when the gates are opened and in their recess in the lock walls, the hand-rails, if it were allowed, would extend above the level of the top of the lock wall and interfere with the movement of the towing lines. A mechanism was, therefore, devised, and interlocked with the miter gate moving machine, by which the hand-rail is automatically lowered when the gate is opened, and raised when the gate is closed. There are 80 motors required for this duty, their rating being 7 H.P.
The chain fenders are operated by means of pumps, and for driving these there are forty-eight motors of 70 H.P. These fender chains are stretched across the lock chambers in front of certain miter gates for the purpose of preventing a ship that might become unmanageable from ramming the gates. The chains are lowered in the floor of the lock chamber whenever it is desired to allow a ship to pass. The mechanism for lifting and lowering the chain consists of a plunger operated by hydraulic pressure, the water for this being furnished by the motor driven pumps.
More than 200 pump motors have been installed. The miter gate sump pumps require ninety-two motors having a rating f 7. H.P. The pump for the drainage sumps at the lower end of each lock utilizes nine motors, also rated at 7 H.P. For the operation of the chain fender sump pumps, forty-eight motors having a capacity of 7 H.P. are used, and for various cable and machinery pits seven motors rated at 7 H.P. To permit the draining of the center wall culverts at intervals, in order to make repairs of the cylindrical valves, there are three semi-portable pumps, one for each lock site. these pumps are of the suspension type and driven by 125 H.P. vertical motors the pump and the motors being mounted rigidly together.
Six emergency dams have been construction, two for each of the lock sites. The purpose of these dams is to check the flow of water through the locks, in case of damage, or in case it should be necessary to make repairs, or to do any work in the locks which would necessitate the shutting off of all water from the lake levels. The dams are placed in pairs in the approaches to the upper locks about 200 feet above the upper guard gates, and each can close the approach to one of the twin locks. Each dam will be operated in four movements: the turning and wedging of the dam and the lowering of the wicket girders and the gates. The machinery for these operations is driven by electric motors, but hand capstans have been provided for use in emergency. The turning machinery is installed in the operator's house, and consists of two 150 H.P. motors for turning the bridge and a limit switch to prevent operation beyond an arc of 90 degrees. A 25 H.P. motor operates the wedges which hold the bridge firmly in place when it is at rest across the channel, or on the lock wall. The machine for raising and lowering of each of the six wicket girders of each dam consists of a hoisting drum driven by a 25 H.P. motor, equipped with a limit switch. the gates on the wicket girders are lowered in place with the assistance of gravity, and, when the dam is to be closed, they will be hoisted out of the water. There are, therefore, six gate-hoisting machines for each dam, each machine driven by a 25 H.P. motor.
Each of the gates in the spillways is operated by motor driven machines erected in a tunnel extending the full length of the spillway dam. There are twenty-two of these gates, of which fourteen are located at Gatun and eight at Miraflores. The motors for operating these gates are rated at 7 H.P.
All the motors utilized at the locks are housed in concrete chambers below the surface of the lock walls in order to insure maximum protection, and interruptions to service are guarded against by installing duplicate sets of transformers for supplying current to them.
It might be asked: "Why was electricity chosen to operate the Panama Canal locks? Why not water, steam or air?" This question is answered by saying that only by the use of electricity would it have been possible to control a set of locks from a central point at each flight of locks, and at the same time to arrange the miniature indicating devices in such a way as to be at all times under the control and observation of the attendant. By the use of electricity it was possible to make a combined control and indicating board, and in no other way could a simple, practicable method of remote operation and indication have been devised, particularly since in some cases the distance between the controlling devices and the operating machinery is greater than 2,700 feet.
The commission engineers specified that the lock control boards should be as nearly as possible an operating miniature of the locks themselves, and so arranged that the indicating devices of the control boards would show the positions of the rising stem and other valves, lock gates, and the water level as it changed in the various locks and in the fore bay. It was also specified that in order to pass a ship through any lock it should be necessary for the control board operator always to maneuver the different operating levers in a definite order corresponding to the pre-determined sequence of operation of the lock machinery necessary to pass the ship quickly and safely through, and that the operator in control of the eastbound channel of the canal must not in any way be able to interfere with the apparatus under the jurisdiction of the operator controlling the westbound channel. The imposed conditions have been fully cared for. Each lock control board indicates to its operator the actual position of the level of the water and of the lock machinery at any instant. Also, by a system of horizontal and vertical interlocking bars beneath the control board, the control handles are so interlocked that only the proper handle or handles can be operated at any time in the course of a ship's travel through the locks.
The interlocking system forces the attendant to operate the chain fenders, gates and valves always in the proper sequence, and also prevents him from operating these devices in incorrect sequence; for instance, opening the gate when the chain fender is not in position or when the valves are open, etc. There is also an interlocking combination that is used in connection with the intermediate gates which divide the locks into short sections. This arrangement is fitted with Yale lock and key so that the intermediate gates can be used only when the attendant has unlocked the combination, this also being subject to the general interlocking system. Certain valves are used to cross-fill between locks. These are are interlocked so that they can be operated only in proper order and combination to equalize the water between a pair of locks and save water which would otherwise be wasted. This cross-filling consists in allowing water from one lock, which is full, to flow into a lock by its side in the other channel until the level of the water is the same in both locks, thus using a portion of the water over gain.
The fact that the control board is a working miniature of the lock which it operates shows the operator the actual condition of the gates, height of water, etc., and consequently, having the whole situation in miniature under his eye he knows what to do next and when to do it; the operator receiving his information as to the movement of the ship from a towing master. the engineers on the locomotives which take ships through the locks, as well as the towing master, can see the position of the gates, but the position of the fender chains is indicated by semaphore arms on the lock walls.
As ships are not permitted to enter the locks or go through on their own power, a special type of towing locomotive has been designed for handling them during transit from one level to another. this constitutes a unique feature of the electrical equipment of the canal. There are forty of these locomotives, each weighing 86,000 pounds, and having an available tractive effort of 47,500 pounds. Mounted in the center of the locomotive body is a windlass having a rope pull of 25,000 pounds. Ordinarily, four of these locomotives will be used to haul ships into and through the locks, two of them on each side, running on tracks parallel to the locks, and obtaining their tractive effort by means of two 75 H.P. totally enclosed motors of the mill type for each locomotive, one motor being direct connected through reduction gearing to the axle. current is supplied by means of contact plows, and the locomotive is propelled on a rack-rail while towing, and while going up or down the step grades between levels. the towing sped is approximately two mils per hour, and while running idle on the return tracks the rack pinion is released and the locomotive is propelled by the regular traction at a speed of five miles per hour, the change from one system of propulsion to the other being effected through gearing by manually operated clutches. The two locomotives astern of the ship act simply as a brake on the ship's movement, the forward locomotives doing the towing.
The windlass cable is operated by two 20 H.P. motors, which are totally enclosed and the cable drum is driven by a friction device which can be set at any desired value—from zero to the full capacity of the motor.
For the supply of coal to naval and merchant ships two coal depots will be provided, located respectively at Cristobal and Balboa. In general, each plant will consist of two water fronts and a storage pile, the water fronts being designated as unloading and reloading wharfs, while the storage pile will consist of a basin for coal, a party of which is to be stored subaqueously, and the remainder piled above it in the dry. The total capacity of the plant at Cristobal will be 300,000 tons, and for Balboa 210,000 tons.
The equipment of the plants will be similar in general construction, and consist of unloading towers, which are self-contained and self-propelled, stocking and reclaiming bridges and reloaders. For the transportation of the coal within the plant a separate conveying system will be arranged. Each reloader will travel on rails laid at the elevation of the decks at the reloading wharves, and will be have a normal capacity of 500 tons per hour.
The operation of the entire equipment, excepting the unloading towers, will be electrical, with suitable sub-stations erected at each plant, and steam power will be used only for the operation of the unloading towers.
In addition to the power applications, electricity is used extensively for lighting purposes as well as for such auxiliary service as the operation of the telegraph system fire alarm, and mining batteries for the defense of the canal. In order that the fortifications may be independent of the main source of electrical supply, they have been provided with small isolated plants equipped with gasoline-electric generating sets.
The success with which the electoral apparatus on the isthmus has met all operating demands serves as an indication of the ability of the designing engineers who were responsible for the detail work, and the possession by the electrical manufacturers of an equipment adequate to meet all the unusual requirements imposed by the remote location and adverse climatic conditions of the Canal Zone.
In this important sphere of the canal equipment, the General Electric Company of Schenectady, N.Y., maintained a dominant position, inasmuch as its factories produced more than one-half of the electrical apparatus used during the construction period, and practically the entire equipment for the generation, distribution, and application of electric energy for the permanent operation of the canal proper, the coaling stations at both terminals, machine shops and other auxiliaries.