Chapter 5

The first thing to do is to get the cable drawn into the ducts, and on the proper accomplishment of this depends to a great extent the success or failure of the whole installation. Probably the ducts have been wired when the subway was constructed, but if not a wire must be run through as a means of pulling in the draw rope. There are several kinds of apparatus for getting a wire through a duct--rods, flexible tapes, mechanical "creepers," etc.; but probably the best is the sectional rod. This simply consists of three or four foot lengths of hard wood rods, having metal tips that screw into each other. A rod is placed in a duct at a manhole, one screwed to that, both are pushed forward, another one added and pushed forward, and so on until they extend the entire length of the duct. Then the wire is attached and the rods are pulled out and detached one at a time and with the last rod the wire is through. At least No. 14 galvanized iron or steel wire should be used, for any smaller size cannot be used a second time, as a rule. In starting to pull in the draw rope a wire brush should be attached to the wire and to this again the rope, and when the brush arrives at the distant end of the duct it very likely will bring with it a miscellaneous collection of material which for the good of the cable had better be in the manhole than in the duct.

The reel or drum carrying the cable should be mounted on wheels or jacks and placed on the same side of the manhole as the duct into which the cable is to be drawn, and must always be so placed that the cable will run off the top of the reel.

There are several methods of attaching the draw rope to the cable. As simple and strong a method as any is to punch two of these holes through the cable, lead and all, and attach the rope by means of an iron wire--some of the draw wire will do--run through these holes. Depending on the length and weight of cable to be pulled it can be drawn either by hand or by a multiplying winch. The rope should run through a block fastened in the manhole in such a position that the rope shall have a good straightaway lead from the mouth of the duct.

The strain on the cable should be perfectly uniform and steady; if the power is applied by a series of jerks either the lead covering may be pulled apart or some of the conductors broken. At the reel there must always be a large enough number of men to turn it and keep the cable from rubbing on anything, and in the manhole one or more men to see that the cable feeds into the duct straight and to guide it if necessary. If the ducts are of iron and are not perfectly smooth at the ends, these should be made so with a file, and in addition a protector of some sort should be placed in the mouths of the duct, both above and below the cable. Six inches of lead pipe, split lengthwise and bent over at one end to prevent being drawn into the duct with the cable, makes a very good protector. The cable should be reeled off the drum just fast enough to prevent any of the power used in pulling the cable through the duct being utilized in unreeling it. If this latter is allowed to occur the cable will be bent too short and the lead covering buckled or broken, and also the cable may be jammed against the upper edge of the duct and perhaps cut through.

If the reel is allowed to turn faster than the cable is drawn in, the first three or four turns on the reel will slacken up, and the lead covering may either be dented or cut through by scraping on the ground. If the cable end when pulled through up to the block is not long enough to bend around the hole more than half way, the rope should be unfastened from its end, a length of rope with a well frayed out end should be run through the block, and by fastening to the cable close to the duct, with a series of half hitches, as much slack as necessary can be pulled in. If this is properly manipulated there need not be a scratch on the cable, but unless great care is taken the lead may be pressed up into ridges and the core itself damaged.

Immediately after the cable is drawn in, if the joint is not to be at once made, the open end or ends should be cut off and the cable soldered up, as most cables are very susceptible to moisture and readily absorb water even from the atmosphere. Where practicable it is always a good plan to pull the cable through as many manholes as possible without cutting the cable; for the joint is, especially in telephone or telegraph cables, the weak point. To do this the rope should be pulled through the proper duct in the next section without unfastening it from the cable; the winch should be moved to the next manhole, and pulling through then done as before. There should always be a man in every hole through which the cable is running to see that it does not bind anywhere and to keep protectors around the cable.

It is not advisable to pull more than one cable into a duct, and never advisable to pull a cable into a duct containing another cable, but if two or more cables have to go into the same duct, they should always be drawn in together. Lead covered cables and those with no lead on the outside should never be pulled into the same duct, for if they bind anywhere the soft cable will suffer where two lead covered cables would get through all right. Some manufacturers are now putting on their cables a tape or braid covering, which saves the lead many bad bruises and cuts, and is a valuable addition to a cable at very little additional expense.

Practically all electric light and power cables are either single or double conductors, and the jointing of these is comparatively a simple matter, although requiring considerable care. The lead is cut back from each end about four or five inches, and the conductors bared of insulation for two or three inches. The bare conductors should be thoroughly tinned by dipping in the metal pot or pouring the melted solder over them. A sperm candle is better than resin or acid for any part of the operations where solder is used. A lead sleeve is here slipped back over the cable, out of the way, and the ends of the conductors brought together in a copper sleeve which is then sweated to a firm joint. This part must be as good a piece of work mechanically as electrically. The bare splice is then wrapped tightly with cotton or silk tape to a thickness slightly greater than that of the insulation of the cable, and is thoroughly saturated with the insulating compound until all moisture previously absorbed by the tape is driven off.

The lead sleeve is then brought over the splice and wiped to the cable. The joint is then filled with the insulating compound poured through holes in the top of the sleeve; these holes are then closed and the joint is complete, and there is no reason why, in light and power cables, that joint should not be as perfect as any other part of the cable. When the cable ends are prepared for jointing they should be hung up in such a position that they are in the same plane, both horizontal and vertically, and firmly secured there, so that when the lead sleeve is wiped on the conductor may be in its exact center, and great care must be taken not to move the cables again until the sleeve is filled and the insulation sufficiently cooled to hold the conductor in position.

It is also very important to see that there are no sharp points on the conductors themselves, on the copper sleeve, on the edges of the lead covering or on the lead sleeve. All these should be made perfectly smooth, for points facilitate disruptive discharges. Branch joints had better be made as T-joints rather than as Y-joints, for they are better electrically and mechanically, although they occupy more room in the manholes. They are of course made in the same way as straight joints, a lead T-sleeve being used, however. For multiple arc circuits copper T-sleeves and for series circuits copper L-sleeves are used.

Telephone and telegraph cables are made of any required gauge of wire and with from 1 to 150 conductors in a cable. In jointing these the splices are never soldered, the conductors being joined either with a twist joint or with the so-called Western Union splice. Each splice is covered with a cotton or silk sleeve or a wrapping of tape, the latter being preferable, although considerably increasing the time necessary for making the joint. Great care must be taken that no ends of wire are left sticking up, for they will surely work their way through the tape and grounds, and crosses will be the result. The wires should always be joined layer to layer and each splice very tightly taped in order to get as much insulating compound around each splice as possible in the limited space. The splices should be "broken" as much as possible, so as to avoid having adjoining splices coming over each other. After the joint has been saturated with insulating compound the wires should have an outside wrapping of tape to keep them in shape, and then the sleeve is wiped on and filled. If the insulation resistance of the jointed telegraph or telephone cable is a quarter of what the cable tested in the factory, it may be considered that an exceptionally good piece of work has been done. I have spoken more particularly of fibrous lead covered cables, as the handling of them includes practically every step of the work on any other kind of underground cable. In insulating dry core paper cables a paper sleeve is slipped over the splice, and in rubber cables the splice is wrapped with rubber tape; all other details are the same for these as for the fibrous cable.

In the laying of light and power cables every joint, as made, should be tested for insulation with a Thomson galvanometer, as the insulation must necessarily be very high, and if one joint or section of cable is any weaker than another it may be very important in the future to know it. All tests must be made after the joint has cooled, for while hot its insulation resistance will be very low.

Tests for copper resistance should also be made to determine if the splices are electrically perfect; an imperfect splice may cause considerable trouble. In telegraph and telephone cables the conductors should be of very soft copper, for in stripping the conductor of insulation it is very easy to nick the wire, and if of hard drawn copper open wires will be the result.

All work should be frequently tested for continuity with telephones, magnetos, or small portable galvanometers. It is only necessary to ground the conductors at one end and try each wire at the other end. For this sort of work a telephone receiver used with one cell of some dry battery is most convenient, and has the additional advantage of affording a means of communication while testing, and is by far the best thing for identifying and tagging conductors.

These cables should be frequently tested during the progress of the work for grounds and crosses with a Thomson instrument, and when the cable is complete, a careful series of tests of the capacity, insulation resistance, and copper resistance of each wire should be made and the exact condition of the cable determined before it is put in service, and thereafter an intelligent oversight of the condition of the circuits can thus be more readily maintained.

Where a company has extensive underground service, a regular cable gang should be in its employ, for quick and safe handling of cables demands the employment of men accustomed to the work. If the cable has been properly laid and tests show it to be in good condition before current is turned on, almost the only trouble to be anticipated will be due to mechanical injury. Disruptive discharge, puncturing the lead, may occur; but the small chance of its occurring can be greatly lessened by the use of some kind of "cable protector," which will provide for the spark an artificial path of less resistance than the dielectric of the condenser, which the cable in fact becomes.

If a fault suddenly develops on a circuit, the chances are it will be found in a manhole, and an inspection of the cable in the manhole will generally reveal the trouble without resorting to locating with a Wheatstone bridge. The cable is often cut through at the edge of the duct, or damaged by something falling on it, or by some one "walking all over it." To guard against these, the ducts should always be fitted with protectors both above and below the cable. The cables should never be left across the manholes, for they then answer the purpose of a ladder, but should be bent, around the walls of the hole and securely fastened with lead straps, that they may not be moved and the lead gradually worn through.

In telegraph cables, when one or two conductors "go," it will probably be useless to look for trouble except with instruments; but if several wires are "lost" at once it will probably be found to be caused by mechanical injury, which can be located by inspection. If it is ever necessary to loop out conductors, a joint can be readily opened and the conductors wanted picked out and connected into the branch cable and the joint again closed without disturbing the working wires. In doing this a split sleeve must be used, and the only additional precaution to be taken is in filling the sleeve to have the insulating compound not hot enough to melt the solder and open up the split in the sleeve. In cutting in service on light and power cables it is entirely practicable to do so without interruption of service on multiple arc circuits, even those of very high voltage; but they require great precaution and involve considerable risk to the jointer, and where possible the circuit to which the connection is to be made should previously be cut dead. Where the voltage is not dangerous to human life, almost any service connection can be made without interruption of service.

I have only indicated a very few of the operations that may be found necessary, and the probable causes of troubles that may be encountered in the operating of underground circuits, believing that the different problems that arise can, with a little experience, be successfully met by any one who has a fair knowledge of the original construction of cable lines.--_Electrical World_.

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RAILROADS TO THE CLOUDS.

If George Stephenson, when he placed the first locomotive on the track and guaranteed it a speed of six miles an hour, could have foreseen that in less than eighty years the successors of his rude machine would be climbing the sides of mountain ranges, piercing gorges hitherto deemed inaccessible, crossing ravines on bridges higher than the dome of St. Paul's, and traversing the bowels of the earth by means of tunnels, no doubt his big blue eyes would have stood out with wonder and amazement. But he foresaw nothing of the kind; the only problem present in his mind was how to get goods from the seaports in western England to London as easily and cheaply as possible, and to do this he substituted for horses, which had for 150 years been drawing cars along wooden or iron tracks, the wonderful machine which has revolutionized the freight and passenger traffic of the world.

It was, indeed, impossible for any one to foresee the triumphs of engineering which have accompanied the advances in transportation. To the engineer of the present day there are no impossibilities. The engineer is a wizard at whose command space and matter are annihilated. The highest mountain, the deepest valley, has no terrors for him. He can bridge the latter and encircle or tunnel the former. The only requisites which he demands are that something in his line be needed, and that the money is forthcoming to defray the expense, and the thing will be done. But the railroad he is asked to construct must be necessary, and the necessity must be plainly shown, or no funds will be advanced; and although the theory does not invariably hold good, especially when a craze for railroad building is raging, as a rule no expense for the construction of a road will be incurred without a prospect of remuneration.

Hence the need of railroad communication has caused lines to be constructed through districts where only a few years ago the thing would have been deemed impossible. The Pacific roads of this country were a necessity long before their construction, and in the face of difficulties almost insuperable were carried to successful completion. So, also, of the railroads in the Andes of South America. The famous road from Callao through the heart of Peru is one of the highest mountain roads in the world, as well as of the most difficult construction. The grades are often of 300 feet and more to the mile, and when the mountains were reached so great were the difficulties the engineers were forced to confront that in some places laborers were lowered from cliffs by ropes in order that, with toil and difficulty, they might carve a foothold in order to begin the cutting for the roadway.

In some sections tunnels are more numerous than open cuts, and so far as the road has gone sixty-one tunnels, great and small, have been constructed, aggregating over 20,000 feet in length. The road attains a height of 15,000 feet above the level of the sea, and at the highest point of the track is about as high as the topmost peak of Mont Blanc. It pierces the range above it by a tunnel 3,847 feet long. The stern necessities of business compelled the construction of this road, otherwise it never would have been begun.

The tunnels of the Andes, however, do not bear comparison with the tunnels, bridges, and snow sheds of the Union Pacific, nor do even these compare with the vast undertakings in the Alps--three great tunnels of nine to eleven miles in length, which have been prepared for the transit of travelers and freight. The requirements of business necessitated the piercing of the Alps, and as soon as the necessity was shown, funds in abundance were forthcoming for the enterprise.

But tunneling a mountain is a different thing from climbing it. Many years ago the attention of inventors was directed to the practicability of constructing a railroad up the side of a mountain on grades which, to an ordinary engine, were quite impossible. The improvements in locomotives twenty-five and thirty years ago rendered them capable of climbing grades which, in the early days of railroad engineering, were deemed out of the question. The improvements proved a serious stumbling block in the way of the inventors, who found that an ordinary locomotive was able to climb a much steeper grade than was commonly supposed. The first railroads were laid almost level, but it was soon discovered that a grade of a few feet to the mile was no impediment to progress, and gradually the grade was steepened.

The inventors of mountain railroad transportation might have been discouraged by this discovery, but it is a characteristic of an inventor that he is not set back by opposition, which, in fact, only serves to stimulate his zeal. The projectors of inclined roads and mountain engines kept steadily on, and in France, Germany, England, and the United States many experimental roads were constructed, each of a few hundred yards in length, and locomotive models were built and put in motion to the amazement of the general public, who jeered alike at the contrivances and the contrivers, deeming the former impracticable and the latter crazy.

But the idea of building a road up the side of a hill was not to be dismissed. There was money in it for the successful man, so the cranky inventors kept on at work in spite of the jeers of the rabble and the discouragements of capitalists loath to invest their money in an uncertain scheme. To the energy and perseverance of railroad inventors the success of the mountain railroad is due, as also is the construction of the various mountain roads, of which the road up Mt. Washington, finished in 1868, was the first, and the road up Pike's Peak, completed the other day, was the latest.

Of all the mountain roads which have been constructed since the one up Mt. Washington was finished, the best known is that which ascends the world-famous Rigi. With the exception of Mont Blanc, Rigi is, perhaps, the best known of any peak in the Alps, though it is by no means the highest, its summit being but 5,905 feet above the level of the sea. Although scarcely more than a third of the height of some other mountains in the Alps, it seems much higher because of its isolated position. Standing as it does between lakes Lucerne, Zug, and Lowertz, it commands a series of fine views in every direction, and he who looks from the summit of Rigi, if he does no other traveling in Switzerland, can gain a fair idea of the Swiss mountain scenery. Many of the most noted peaks are in sight, and from the Rigi can be seen the three lakes beneath, the villages which here and there dot the shores, and, further on, the mighty Alps, with their glaciers and eternal snows.

Many years ago a hotel was built on the summit of the Rigi for the benefit of the tourists who daily flocked to this remarkable peak to enjoy the benefit of its wonderful scenery. The mountain is densely wooded save where the trees have been cut away to clear the land for pastures. The ease of its ascent by the six or eight mule paths which had been made, the gradual and almost regular slope, and the throngs of travelers who resorted to it, made it a favorable place for an experiment, and to Rigi went the engineers in order to ascertain the practicability of such a road. The credit of the designs is due to a German engineer named Regenbach, who, about the year 1861, designed the idea of a mountain road, and drew up plans not only for the bed but also for the engine and cars. The scheme dragged. Capitalists were slow to invest their money in what they deemed a wild and impracticable undertaking, and even the owners of the land on the Rigi were reluctant for such an experiment to be tried. But Regenbach persevered, and toward the close of the decade the inhabitants of Vitznau, at the base of the Rigi, were astonished to see gangs of laborers begin the work of making a clearing through the forests on the mountain slope. They inquired what it meant, and were told that a road up the Rigi was to be made. The Vitznauers were delighted, for they had no roads, and there was not a wheeled vehicle in the town, nor a highway by which it could be brought thither. The idea of a railroad in their desolate mountain region, and, above all, a railroad up the Rigi, never entered their heads, and a report which some time after obtained currency in the town, that the laborers were beginning the construction of a railroad, was greeted with a shout of derision.

Nevertheless, that was the beginning of the Rigi line, and in May, 1871, the road was opened for traffic. It begins at Vitznau, on Lake Lucerne, and extends to the border of the canton and almost to the top of the mountain. It is 19,000 feet long, and during that distance rises 4,000 feet at an average grade of 1 foot in 4. Though steep, it is by no means so much so as the Mt. Washington road, which rises 5,285 feet above the sea, at an average of 1 foot in 3. There are, however, stretches of the Rigi road at which the grade is about 1 foot in 2½, which is believed to be the steepest in the world.