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ELECTRIC LOCOMOTIVE DRAWING "TWENTIETH CENTURY LIMITED.'
miles of its main lines, making one hundred miles of single track, electrified by what is called the single-phase system. But the New York Central has thirtythree miles of four-tracked line, or 132 miles of single track, electrified by what is known as the continuous or direct current system. Now these two roads use the same depot in New York City. Practically all the New England railway service into New York City is over the four tracks of the New Haven line to a point twelve miles out from the Grand Central station, where the trains pass at full speed to the tracks of the New York Central over which they complete their run to the terminal. For the twenty-one miles of the run on the New Haven tracks the trains are operated from overhead trolley wires by alternating current taken aboard the locomotive at 11,OCX) volts. For the twelve miles on the New York Central tracks they are operated from the third rail by direct current at 650 volts. When the New Haven de
cided to electrify that twenty-one miles of its own lines it was face to face with the restriction imposed by those twelve miles of New York Central lines. Yet it decided in favor of the alternating current in spite of the twelve miles over which it would have only the direct current available.
The Erie Railway has thirty-four miles of single-phase electrification. The Pennsylvania has seventy-five miles of the direct current system. The West Shore has 106 miles of continuous current electrification, the Long Island Railroad has 125 miles, the West Jersey and Seashore 150 miles, and the Baltimore and Ohio seven miles. On the other hand, the Grand Trunk has twelve miles of the other system, the Colorado Southern forty-six miles, and the Baltimore and Annapolis Shortline thirty miles. There is a greater diversity in Europe. In Italy there is a considerable mileage operated by what is known as the three-phase system. The same system is used in the Simplon Tunnel and on the Gergal Santa Fe in Spain. The other two systems are used extensively in the countries of Europe. The three-phase system is used for a tunnel on the Great Northern line in the United States.
A PENNSYLVANIA ELECTRIC LOCOMOTIVE WITH TRAIN OF ALL STEEL CARS KOK USF. IN THE
HUDSON RIVER TUNNEL.
Now it is the opinion of those competent to form opinions upon so difficult a subject that what has been done in a small way by these and other lines will in time be done by the railroads throughout the country, and over long reaches of their lines, if not over their entire systems. In time these roads will face each other at meeting points in hundreds of places. Then will come the rub, the inconvenience and the outlay. If
railroads with different systems of electrification are 3 thousand miles, or a hundred miles, or ten miles apart, it makes "no difference whether they have their contact conductors in the same position or whether they use an electric current of the same character. But when they come together it will cost much money and cause manifold delays and vexations if their systems are unlike. It is here that the clanger and the problem of the future emerge.
There was an analogous problem to be solved by the railroads thirty years ago. Its solution entailed financial burdens which lay upon them very heavily for many years. In 1878 in this country there were no less than twelve different gauges of railroad tracks, the standard gauge of four feet eight and one-half inches, and eleven others. By that time it had become evident that uniformity of gauge in the United States and Canada was absolutely necessary. In the early days of railroading the differences of gauge were of no moment. No one dreamed of an interchange of traffic, of using the engines and cars of one railroad upon the lines of another. Some men argued that it was an advantage to keep to a gauge that would prevent the engines and cars of a connecting line from running on its tracks. In some cases through passengers were kept in their cars while the trucks under the coaches were changed, and thus they went on to their destinations without change, although they ran over tracks of five feet, five feet six inches, and six feet gauges in succession. In time, in spite of the immense expense entailed by the change of gauge and of equipment, all the lines made their tracks conform to the present standard gauge.
This experience of thirty years ago explains the view of electrification that is held by the far-sighted and broadminded railroad men of today. They fear that each road will consider its plans with reference only to its own needs, that the road will treat its project as an isolated case. They desire that the roads shall take into consideration in addition the electrification of railroads in general, thus avoiding at some time in the future an expensive experience analogous to that involved in the gauge prohlem of thirty years ago. The problem of today, in view of the strides electrification is certain to make in the near future, is that involved in the selection of a general system of electrification, a system which shall be in its domain what the standard gauge has been in another department of railroading. Determine upon a standard system, which will make possible a complete interchange of traffic, and which will admit of the greatest extension of electrification, and in the future vast expense, and delay, and vexatious difficulties will be avoided.
The three systems of electrification now in use have their respective advan
tages. Each has its own method of conveying the power from the generating station to the locomotive, and each has its own type of motor. The three-phase system in successful use in Italy and Switzerland has been before the world for a number of years. The government of Italy is at present installing upon a heavy-grade line out of Genoa a service for which thirty-five Kxromotives rated at 2,000 horse-power arc now being built. This is the system
Arrangement Of Motors Over Driving Axles. For the Binvlc-phaso and direct current locomotm—passenger and freight service—on the New York. New Haven and Hartford Railroad.
which is used in the Cascade tunnel by the Great Northern. The alternating current is used with two overhead trolley wires.
The third rail system is now being extensively used for direct current. There are no overhead wires and in place of the trolley a third rail is used from which current is collected by a shoe sliding upon it. At present the general practice, except on very short lines, is to produce or generate alternating current at the power house and change this to direct current of proper voltage at sub-stations distributed along the line. The sub-station equipment includes transformers, converters or motor generators, and switchboard apparatus. This system has a large loss in power between the power house and car and the cost of equipment is quite high. The single-phase system uses an alternating current and a single overhead wire. Just now the eyes of the railroad world are upon the daring innovation which has been put into use by the New York, New Haven and Hartford, which line has made the most important installation of this system thus far undertaken.
Each of these three systems has its own type of motor with important differences in speed performances. The directcurrent motor is a sort of automaton, that is, it automatically adjusts its speed to its load. If the weight of the train is increased, or the grade becomes steeper, the speed slows in proportion. If the load and the grade remain constant the speed will not vary unless the voltage applied to the motor is increased. But the system of current supply implies a fixed voltage, and therefore even in emergencies it would be impossible to get a speed much above that for which the motor was constructed. On the other hand, the speed may be cut in half or it may be quartered. This is done by connecting the motors in series, dividing the pressure between two or between four motors, and by the use of electrical resistance. There are other practical objections to this system.
The motor of the three-phase system is inherently a constant-speed machine. With a light load or a heavy load it runs at the same rate of speed. Upgrade or on a level track it makes approximately the same speed also. But the high power required to climb the grade may be several times that needed on the level. On the other hand, however, the motor makes no greater speed on the level track than on an ascent. There are
various devices by which lower speeds can be secured, all of them involving complications and losses. In no way can the speed be more than a trifle higher with a light load than with a heavy train. The motors are comparatively simple in construction, and when on a down grade they may return current to the line, a valuable thing among the mountains.
The speed characteristics of the single-phase series motor are similar to those of the direct-current motor. The speed at a given voltage is more or less as the load is lighter or heavier. But this motor has the advantage over others that by a simple controller its speed may be greatly varied according to conditions. Many voltages lower than the normal may be provided for lower speeds and various higher voltages to produce speeds above the normal. The steam locomotive has its throttle lever, and the single-phase electric its control lever, and in both cases the lever may be placed in any one of many notches to keep the required speed. The current comes aboard the locomotive at a voltage of 11,000 volts on the New Haven lines. But the motors do not use the current at such a high voltage. It is reduced by the transformers which are installed in the locomotives. As will be noted farther on, this means the elimination of the substation, a bold departure, with many advantages. It is the possibility of adjustment, of setting the lever for different speeds, which is a very valuable feature of this system. The limit of endurance with the vast supply of energy thus made available is determined by the safe temperature of the motor. In the steam locomotive ability to maintain speed with heavy loads depended upon the capacity of the boiler.
When it comes to the expense consideration the differences in these three systems is a matter not of motors primarily or of power-houses, but of the transmisTrain The
sion of the power from the latter to the former. In the power-houses almost always the current that is generated is the alternating and at high tension. It is cheaper to transmit it even when for use it has to be converted into direct current.
Each of the systems has a number of links or elements through which the power must pass between the moment of its generation in the power house and its application in the locomotive.
In the continuous current system using alternating current for transmission there must be a sub-station between the power-house and the locomotive. The current is generated in the power-house, raised by transformers to high voltage, carried by wires to sub-stations miles away, where transformers or motor generators step it clown to a voltage low enough to use and converters change it from alternating to direct current: it is then carried by wires to the third rail or trolley wire.
In the case of the three phase system the current once generated is raised by transformers to high voltages, carried to substations about eight miles apart, and stepped down by transformers to low voltage, or the high voltage current may be carried directly to the two overhead trolley wires. In the latter case the voltage is stepped down by transformers on the locomotive. The low voltage three phase current is then fed directly to the motor. Two overhead wires are used and this involves a double system of overhead construction, which becomes quite complicated at cross-over switches. The wires have to be kept well separated and insulated from each other at equal heights above the train. The track in this system acts as a third wire or conductor. In the direct current system the return circuit is furnished by the track.
To get the current aboard the locomotive in the single-phase system, it may
For Suburban Srsvicb On The New Haven Line. new form of overhead construction is clearly shown.
be generated in the power-house, raised by transformers to high voltage, carried by wires to sub-stations, widely-separated, where it is stepped down to a usable tension, and carried to a single wire strung over the railroad tracks. The single wire permits a wide range in height as the trolley adjusts itself automatically to the position of the wire. Usually the wire is strung on lines twenty-two feet above the track but passes under bridges at a height of fifteen and one-half feet. Once more the track acts as one side of the circuit.
But a remarkable part of the great feat of the New Haven was that it abolished the sub-station where the transformers intervened between the locomotive and the power-house. It took the current at high tension aboard the locomotive itself. This it could do because the length of the line on which the service was installed 'was but twenty-one miles. It was a daring bit of pioneer work to take the high voltage alternating current aboard the locomotive and lower it there to the low voltage current required for the motors, doing aboard the speeding locomotive what had been done in the sub-stations scattered along the railroad