« PreviousContinue »
miles of its main lines, making one hun- cided to clectrify that twenty-one miles dred miles of single track, electrified by of its own lines it was face to face with what is called the single-phase system. the restriction imposed by those twelve But the New York Central has thirty- miles of New York Central lines. Yet it three miles of four-tracked line, or 132 decided in favor of the alternating curmiles of single track, electrified by what rent in spite of the twelve miles over is known as the continuous or direct which it would have only the direct curcurrent system. Now these two roads rent available. use the same depot in New York City. The Erie Railway has thirty-four Practically all the New England railway miles of single-phase electrification. The service into New York City is over the Pennsylvania
Pennsylvania has seventy-five miles four tracks of the New Haven line to a of the direct current system. The West point twelve miles out from the Grand Shore has 106 miles of continuous Central station, where the trains pass at current electrification, the Long Island full speed to the tracks of the New York Railroad has 125 miles, the West Central over which they complete their Jersey and Seashore 150 miles, and the run to the terminal. For the twenty-one Baltimore and Ohio seven miles. On miles of the run on the New Haven the other hand, the Grand Trunk has tracks the trains are operated from over- twelve miles of the other system, the head trolley wires by alternating current Colorado Southern forty-six miles, and taken aboard the locomotive at 11,000 the Baltimore and Annapolis Shortline volts. For the twelve miles on the New thirty miles. There is a greater diversity York Central tracks they are operated in Europe. In Italy there is a considerfrom the third rail by direct current at able mileage operated by what is known 650 volts. When the New Haven de- as the three-phase system. The same
railroads with different systems of electrification are 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 danger 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 inter
change of traffic, of using the OVERHEAD SYSTEM OF CONSTRUCTION ON AN ITALIAN RAILROAD.
engines and cars of one rail
road upon the lines of ansystem is used in the Simplon Tunnel other. Some men argued that it was an and on the Gergal Santa Fe in Spain. advantage to keep to a gauge that would The other two systems are used exten- prevent the engines and cars of a consively in the countries of Europe. The necting line from running on its tracks. three-phase system is used for a tunnel In some cases through passengers were on the Great Northern line in the United kept in their cars while the trucks under States.
the coaches were changed, and thus they Now it is the opinion of those com- went on to their destinations without petent to form opinions upon so diffi- change, although they ran over tracks of cult a subject that what has been done five feet, five feet six inches, and six in a small way by these and other lines feet gauges in succession. In time, in will in time be done by the railroads spite of the immense expense entailed throughout the country, and over long by the change of gauge and of equipreaches of their lines, if not over their ment, all the lines made their tracks conentire systems. In time these roads will form to the present standard gauge. face each other at meeting points in hun- This experience of thirty years ago dreds of places. Then will come the rub, explains the view of electrification that the inconvenience and the outlay. If is held by the far-sighted and broad
RAILWAY PROBLEM OF TOMORROW
minded 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 problem of thirty years ago. The problem of today, in view of the strides electrification is
ARRANGEMENT OF Motors Over Driving AXLES. certain to make in the near For the single-phase and direct current locomotive-passenger and
freight service on the New York. New Haven future, is that involved in the
and Hartford Railroad. selection of a general system of electrification, a system which shall which is used in the Cascade tunnel by be in its domain what the standard gauge the Great Northern. The alternating has been in another department of rail- current is used with two overhead trolroading. Determine upon a standard ley wires. system, which will make possible a com- The third rail system is now being explete interchange of traffic, and which tensively used for direct current. There will admit of the greatest extension of are no overhead wires and in place of the electrification, and in the future vast ex- trolley a third rail is used from which pense, and delay, and vexatious difficul- current is collected by a shoe sliding ties will be avoided.
upon it. At present the general practice, The three systems of electrification except on very short lines, is to pronow in use have their respective advan- duce 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 The PENNSYLVANIA'S ARTICULATOR LOCOMOTIVE FOR THE NEw York
a large loss in power beTUNNEL SERVICE,
tween the power house and The underframe, motors, and driving mechanism are here shown.
car and the cost of equip
ment is quite high. tages. Each has its own method of con- The single-phase system uses an alterveying the power from the generating nating current and a single overhead station to the locomotive, and each wire. Just now the eyes of the railroad has its own type of motor. The world are upon the daring innovation three-phase system in successful use which has been put into use by the New in Italy and Switzerland has been be- York, New Haven and Hartford, which fore the world for a number of years. line has made the most important installaThe government of Italy is at present tion of this system thus far undertaken. installing upon a heavy-grade line out Each of these three systems has its of Genoa a service for which thirty-five own type of motor with important differlocomotives rated at 2,000 horse-power ences in speed performances. The directare now being built. This is the system current motor is a sort of automaton, 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 TYPICAL SECTION. SHOWING THIRD RAIL TRANSMISSION LINE, AND SIGNAL BRIDGE OF ELECTRIFIED PORTION OF THE NEW
may be greatly varied acYork CENTRAL AND HUDSON River RAILROAD.
cording to conditions.
Many voltages lower than that is, it automatically adjusts its speed the normal may be provided for lower to its load. If the weight of the train speeds and various higher voltages to is increased, or the grade becomes produce speeds above the normal. The steeper, the speed slows in proportion. steam locomotive has its throttle lever, If the load and the grade remain con- and the single-phase electric its control stant the speed will not vary unless the lever, and in both cases the lever may be voltage applied to the motor is increased. placed in any one of many notches to But the system of current supply im- keep the required speed. The current plies a fixed voltage, and therefore even comes aboard the locomotive at a voltage in emergencies it would be impossible to of 11,000 volts on the New Haven lines. get a speed much above that for which But the motors do not use the current at the motor was constructed. On the other such a high voltage. It is reduced by the hand, the speed may be cut in half or it transformers which are installed in the may be quartered. This is done by con- locomotives. As will be noted farther necting the motors in series, dividing the on, this means the elimination of the subpressure between two or between four station, a bold departure, with many admotors, and by the use of electrical re- vantages. It is the possibility of adjustsistance. There are other practical ob- ment, of setting the lever for different jections to this system.
speeds, which is a very valuable feature The motor of the three-phase system of this system. The limit of endurance is inherently a constant-speed machine. with the vast supply of energy thus made With a light load or a heavy load it runs available is determined by the safe temat the same rate of speed. Upgrade or perature of the motor. In the steam on a level track it makes approximately locomotive ability to maintain speed the same speed also. But the high power with heavy loads depended upon the carequired to climb the grade may be sev- pacity of the boiler. eral times that needed on the level. On When it comes to the expense considthe other hand, however, the motor eration the differences in these three sysmakes no greater speed on the level tems is a matter not of motors primarily track than on an ascent. There are or of power-houses, but of the transmis
RAILWAY PROBLEM OF TOMORROW
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
TRAIN FOR SUBURBAN SERVICE ON THE NEW HAVEN LINE.
The new form of overhead construction is clearly shown. power-house, raised by transformers to high voltage, carried by wires to sub-stations be generated in the power-house, raised miles away, where transformers by transformers to high voltage, carried motor generators step it down to a volt- by wires to sub-stations, widely-sepaage low enough to use and converters rated, where it is stepped down to a change it from alternating to direct cur- usable tension, and carried to a single rent; it is then carried by wires to the wire strung over the railroad tracks. The third rail or trolley wire.
single wire permits a wide range in In the case of the three phase system height as the trolley adjusts itself autothe current once generated is raised by matically to the position of the wire. transformers to high voltages, carried to Usually the wire is strung on lines substations about eight miles apart, and twenty-two feet above the track but stepped down by transformers to low passes under bridges at a height of fifvoltage, or the high voltage current may teen and one-half feet. Once more the be carried directly to the two overhead track acts as one side of the circuit. trolley wires. In the latter case the volt- But a remarkable part of the great feat age is stepped down by transformers on of the New Haven was that it abolished the locomotive. The low voltage three the sub-station where the transformers phase current is then fed directly to the intervened between the locomotive and motor. Two overhead wires are used the power-house. It took the current at and this involves a double system of high tension aboard the locomotive itself. overhead construction, which becomes This it could do because the length of quite complicated at cross-over switches. the line on which the service was inThe wires have to be kept well separated stalled 'was but twenty-one miles. It and insulated from each other at equal was a daring bit of pioneer work to take heights above the train. The track in the high voltage alternating current this system acts as a third wire or con- aboard the locomotive and lower it there ductor. In the direct current system the to the low voltage current required for return circuit is furnished by the track. the motors, doing aboard the speeding
To get the current aboard the locomo- locomotive what had been done in the tive in the single-phase system, it may sub-stations scattered along the railroad