In 1940 the Bessemer & Lake Erie line began two-way communication on 2mile-long coal and ore trains. The plan did not become general. If a train crew wants to get in touch with a block operator today, the train is stopped and a call made on a track-side telephone. Last December a Florida-bound passenger train was derailed near Lumberton, N. C., one death resulting. A little more than a half-hour later, a north-bound passenger train plowed into the derailed cars, killing about 70 persons. Ever since, with active prodding by Senator Kilgore's committee, people have been asking why our railroads do not use two-way radios on trains to facilitate communication. Such a means of communication would have made it possible to warn the approaching train in time to prevent such a tragic accident as the one near Lumberton. In February of this year, unconnected with this debate, the Pennsylvania Railroad installed a "wired radio" system on one of its branch lines. As a result of this installation, freight train crews can talk with the block operators in wayside towers, the locomotive engineer can talk with the conductor in the caboose, and the crew of one train can even talk with the crew of another train if the two are not more than 4 miles apart. To accomplish this, "carrier" currents are conducted along the rails and along wires strung parallel to the railroad tracks. The wonder in the mind of the average layman is that some such device has not been worked out and installed throughout our railroad systems long ago. Similar systems are also in operation in some railroad yards, including one in West Chicago, where classification of cars is speeded up. However, the Association of American Railroads is lukewarm about such systems. Col. Robert S. Henry of that organization pictures the confusion that would come if all the conductors or engineers on 25 trains going north and 30 trains going south, between New York and Washington, wanted to talk to Philadelphia at the same time. The caricature is amusing but hardly convincing, for the same confusion would result if all a city's patrol cars wanted to talk with headquarters at the same time or all planes converging on a busy airport tried to contact the field simultaneously. A wider extension of this safety device is plainly feasible, if the railroads will simply recognize the need for it. Senator H. M. KILGORE, EXHIBIT No. 400 [Telegram] JUNE 1, 1944. Subcommittee on War Mobilization, Washington, D. C.: Recent tests of intertrain and interyard communication on Rio Grande indicate desirability of such facilities as wartime measure toward speeding up and providing additional safety of movement of essential traffic. We have applied to Federal Communications Commission and War Production Board for license make installation on permanent basis. If such license granted our intention make installation and expend same rapidly as conditions will permit. In meantime we are continuing our investigation various types equipment. E. H. MUSGROVE, Denver & Rio Grande Western Railroad. EXHIBIT NO. 401 ASSOCIATION OF AMERICAN RAILROADS, To Public Relations Representatives: In connection with the same subject, there is enclosed also a reprint of an article in the February 12, 1944, issue of Railway Age, describing a recent installation of train communication on the Belvidere branch of the Pennsylvania Railroad. Very truly yours, ROBERT S. HENRY, Assistant to the President. TRAIN COMMUNICATION-AN OUTLINE OF THE DEVELOPMENT OF SYSTEMS OF COMMUNICATION WITH AND ON MOVING TRAINS, 1914–43 Railroads began experiment and work looking toward the development of a satisfactory system of communication with moving trains with an installation on the Delaware, Lackawanna & Western in 1914. In 1920 the New York Central, working with Major General Squier, United States Army, retired, who was chief signal officer during World War No. 1, and with the DeForest Wireless Co., began experiments with the so-called wiredwireless, in which messages are transmitted through carrier circuits using the rails and the wayside wires along the railroad. In the same year the Pennsylvania Railroad began experiments with telephone communication to and from its tugs in New York Harbor-the beginning of a system which 10 years later was taken up in connection with New York City's fire boats, and which is now part of the regular telephone service in the New York area. In this same year of 1920, experiments were begun on the electrified section of the Chicago, Milwaukee & St. Paul Railroad in Montana, looing toward the use of the electric trolley wires as a means of train communication. Somewhat similar experiments were conducted by the New York Central and the General Electric Co. in New York in the following year. Beginning in the year 1922 a special research committee of the telegraph and telephone section of the American Railway Association (the predecessor of the Association of American Railroads) began work with the Radio Corporation of America, the American Telephone & Telegraph Co., the Westinghouse Electric & Manufacturing Co., the General Electric Co., the Western Electric Co., and individuals and other companies who were working on radio problems. In the year 1924 the Norfolk & Western Railroad and the Westinghouse Co. cooperated in an experimental installation. In 1926 the New York Central and the Zenith Radio Corporation experimented between Englewood, Ill., and Elkhart, Ind., using pure wireless as distinguished from the carrier circuit or "wired-wireless" method. Pure wireless was also tried by the New York Central with General Electric equipment between Selkirk yard and Utica, N. Y., in the following year. In 1928 the Chesapeake and Ohio and the Westinghouse Co. tried out an installation of the space radio type. The same installation was afterward rebuilt to take advantage of what was learned in its experimental use and was tried out on the Pennsylvnia Railroad, between Altoona and Enola yard, Pa. In 1929 studies were begun on the application of either radio or carrier circuit communication to large switching yards of the gravity or hump type. In the year 1930 the Canadian National installed commercial public telephone service on its trains between Montreal and Toronto, making it possible for passengers to be connected with any telephone of the Bell System in that section. The service was widely advertised but was so little used by passengers that after a few months it was discontinued for lack of public patronage. In this same year of 1930 the Federal Radio Commission withdrew the licenses for wave bands heretofore assigned for railroad use, causing the railroads and the companies with which they were working to start new tests with ultra-high frequency wave lengths and under special experimental license only. Using these ultra-high frequencies, experiments were conducted in 1934 by the Central Railroad of New Jersey and the Radio Corporation of America, between Jersey City and Scranton, Pa. Radio Corporation of America equipment was also used in an experiment on the New York, New Haven and Hartford Railroad. On the same railroad, in 1934, Westinghouse equipment was used in experimental installations between Cedar Hill yard (New Haven) and Springfield, Mass., and between Cedar Hill and Maybrook, N. Y. It was also tried out in the operation of the hump yard of the New Haven at Cedar Hill. Beginning in 1933 and continuing until 1937, the Pennsylvania Railroad and the Radio Corporation of America carried on experiments using radio, while from 1936 on the Pennsylvania and the Union Switch & Signal Co., and the Pennsylvania and the General Electric Co., tried out experimental installations of the carrier circuit type. In 1939 the Great Northern experimented with the use of trolley wires in electrified territory. Ship-to-shore radio communication was installed in that year on the train ferries of the Ann Arbor Railroad crossing Lake Michigan. Like systems have been installed also on the other railroad car ferries on the Lakes. In 1940 the New York Central installed in its Sharonville, Ohio, yard (near Cincinnati) a two-way system of communication known as the Clark "railfone." After thorough trial it was found not successful and has since been replaced by the carrier circuit system of the Union Switch & Signal Co. This Union Switch & Signal system was also installed in the same year in the DeCoursey, Ky., yard of the Louisville & Nashville and in yard B of the Pennsylvania at Columbus, Ohio. Subsequently, a like system has been installed in the Roanoke, Va., yard of the Norfolk & Western. Experiments looking toward the use of the carrier circuit system of the Union Switch & Signal Co. in main line operations began on the Bessemer & Lake Erie Railroad in 1937. In 1939 an experimental installation was made on the Birmingham Southern, an 18-mile line in the Birmingtom, Ala., industrial district. In 1941 a more extensive experimental installation was made on the Belvidere branch of the Pennsylvania Railroad, extending from Trenton to Philipsburg, N. J., a distance of 50 miles. Numerous technical and operating problems were encountered in the operation of the system on this branch, which has a traffic density of 4 passenger trains and 10 to 12 freight trains daily, and the system is still considered experimental. The results obtained, however, justified the publication of a report on the system in the Railway Age of February 12, 1944. In addition to these developments with the carrier circuit system, which uses rails and the wayside wires as part of its "wired-wireless" transmission experiment has gone forward in the use of space radio without carrier circuits, or pure radio. One such installation was that made at the Proviso yard of the Chicago & North Western by the General Railway Signal Co. The experimental work heretofore done by the railroads and the radio and signal companies utilized frequencies below 40 kilocycles. Since this is the most crowded part of the radio spectrum, with increasing demands for assignments for police use, etc., the Communications Commission has revoked the license granting the use of a wave band for such experimental installations as that at Proviso yard, and recommended experimentation with ultra high-frequencies. Laboratory experiments are now under way looking to the use of these frequencies for train communication. In addition to the usual problems posed by the propagation of radio waves in all directions, a special difficulty encountered in the use of these ultra-high frequencies is the tendency toward what is known as line-of-sight transmission. The effect of this is that signals are not efficiently received except from an antenna high enough to be seen from the point of reception-an effect somewhat like that of television as at present developed. Since the height of bridges, tunnels, and other structures along railroads severly limits the elevation of antennae on railroad equipment (about 30 inches above the roof of the caboose being the practical limit) the use of ultra-high frequencies over considerable distances is not possible at this stage of the development of the art; but the great advances in the electronic art, especially those resulting from military applications during the war, which are still secret, lead to the hope that worthwhile technical improvements will be available coincident with peace. The carrier circuit system requires a track with bonded joints and a wire adjacent to the track-conditions which are not always available. The system as it is at present developed, moreover, utilizes the same frequencies which were already in wide use on the railroads in their carrier circuits, which are superimposed on existing trackside pole lines and which are very important in the transmitting of dispatchers' and other messages along the line of the railroad. The result is a degree of interference between the two systems which has not been entirely resolved. The carrier circuit system is much more expensive to install than the pure radio system. As a safety measure alone, the cost of its installation would not be justified, since the same money applied to the extension of other safety measures, such as grade-crossing elimination or protection, or the extension of automatic safety signals of various sorts, would undoubtely produce a greater saving of life and limb. However, the railroads and the communications companies are carrying on their experiments along both lines, since it is apparent that in different situations different systems might be found most useful. For example, on a switching railroad serving an extended industrial district, with neither bonded rails nor an adjacent pole line of wires, the need for communication between a central office and the switch engines might well be served by a pure radio installation, whereas the cost and complications of a carrier circuit system might not be justified. To sum up, as a result of prolonged and widespread experiments by railroads and communications companies over a period of more than 20 years, there are now open to railroads two possible lines of development, both still in an experimental stage with many difficult technical and practical operating problems yet to be worked out. The carrier circuit system is in practical use in four major yards and on one comparatively busy branch line 50 miles long. The pure radio system, as a result of wave-band difficulties, has been turned back to the laboratory for further experimentation in ultra-high frequency transmission. Undoubtedly development will continue on both lines. TELEPHONE SYSTEM EMPLOYED BY THE PENNSYLVANIA PROVIDES CONTINUOUS COMMUNICATION BETWEEN TRAINS, BETWEEN FRONT AND REAR OF TRAINS, AND BETWEEN TRAINS AND WAYSIDE TOWERS By W. R. Triem, general superintendent of telegraph, Pennsylvania Railroad A long felt need for a means of communication between trains, whether moving or standing, and between trains and wayside stations is believed to have been met in the train telephone system being given trials on the Belvidere branch of the New York division of the Pennsylvania Railroad. This telephone system is the result of joint development by the Pennsylvania and other railroads with the Union Switch & Signal Co. over a period of several years. Since the earliest days of experimentation with radio the railroads and manufacturers of electrical equipment have been attempting to solve the problem of providing reliable communication on and between railroad trains and wayside stations. This innovation is the latest of a long list of improvements developed by the Pennsylvania and other railroads in cooperation with various electrical manufacturers to expedite train movements and afford better service for the public. Discoveries and developments in the field of electronics have been utilized by the railroads in numerous ways, and constant research is under way to find means of further increasing the efficiency of railroad operations. Among more recent contributions in the field of electrical and electronic developments are centralized traffic control, dragging equipment detectors, cab signals, radio-telephone tugboat dispatching, telephone announcing systems in yards and stations, yard engine telephone systems, magnaflux method of examination of axles for cracks, Sperry apparatus for detecting flaws in rails, and the like. Among these, an outstanding contribution to train operation is the cab signal, by means of which a signal is displayed in the cab of a locomotive reproducing wayside signal indications and keeping the engineman constantly advised of the conditions on the track ahead of his train. In the development of this cab signal system it was found that a further extension of the application of electronics to railroad operation was possible, to provide a means of communication between moving trains and between moving trains and wayside stations. PRESENT SYSTEM RESULT OF RESEARCH The train telephone in use on the Pennsylvania Railroad today is a result of these studies. Actually, it is neither radio nor telephone. It incorporates certain features of both types of equipment and eliminates other features of both systems. So far as radio is concerned, it must be remembered that essentially, 1 From the Railway Age, February 12, 1944. communications by radio are broadcast to all suitably tuned receiving sets within transmission distances through ground and atmosphere; i. e., through transmission paths universally provided by nature. Radio would possibly fulfill the requirements of communication between moving trains and between moving trains and wayside stations if it were not necessary to share with others the privilege of the air and conform to Federal rules and regulations so essential to the maintenance of order under crowded and competitive conditions. On the other hand, wire telephony does not fulfill all of the requirements of communication between moving trains and wayside stations for the reason it is confined to definite wire transmission paths from the transmitter to the receiver. The train telephone system in use by the Pennsylvania on the Belvidere branch combines certain features of radio and wire telephony, utilizing the constant contact with moving vehicles possible by radio and at the same time restricting the transmission paths to railroad property. Railroad vehicles invariably use track rails which extend to all areas requiring communication with moving equipment. Thus the rails offer a most desirable communication transmission path. The rails, together with adjacent communication pole lines, are utilized for the transmission paths and the electronic equipment, electronic tubes, condensers, coils, and the like, on locomotive, cabin cars, and wayside stations provide the means of utilizing radio principles in maintaining the constant communication contact so essential to the success of the scheme. Experimental installation of the Union Train Communication System on the Belvidere branch was authorized in September 1941, and in June 1942 a locomotive and cabin car had been equipped, wayside appliances installed and placed in service. To date 10 locomotives, and 10 cabin cars and 1 block station have been equipped and an additional block station will soon be in service. HOW IT WORKS It is a carrier telephone system using the upper side band of a 5,700-cycle carrier for transmitting calling signals and voice. The carrier current is fed conductively into the rails, picked up inductively from the rails, and induced in the wires of the communication line adjacent to the track. It is carried through the rails and line wires between front and read ends of trains, from one train to another train and to wayside stations by direct wire connections in the vicinity of the station. At the sending telephone on the locomotive and cabin car, a circuit is provided by a loop from an insulated truck to adjacent truck via the rails, and a current at carrier frequency is sent out along the rails and adjacent line wires with the return path through the ground. The impedance drop in the rails between the insulated truck and adjacent truck causes the transmitting rail voltage. Receivers pick up the energy which is transmitted through induction coils in proximity of the rails and is amplified and demodulated for reception in the loudspeakers and handset telephones. At the station, the output or transmitting connections from the set, when talking or signaling, are made to a simplex leg of a block line and to the rail system, the circuit being completed by the capacity coupling between the block line and the rails the length of the branch. The receiving connections at the station are made to the track rails at points about 150 feet apart, the impedance drop of which provides the energy which is amplified and demodulated for reception. There is no interference in operation between this system and radio, telephone, or signaling systems. TRAIN EQUIPMENT The locomotive and cabin-car equipment consists of a weather-proof instru-. ment shelter containing electron tubes, condensers, coils, dynamotor, fuses, etc.; a source of power supply; an output transformer; two receiving coils; a loudspeaker; a control box; necessary wiring and conduit. The equipment box or instrument shelter on the locomotive is located on the running board near the front end, the output transformer is in front of and below the smokebox, the receiving coils are about 4 inches above the top of each rail and located between the engine truck and front drivers, the loud speaker is in the roof of the cab above engineman, the control box with calling button, indication lamps, volume control and handset is in the cab above and in front of engineman. |