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Railroad Radio
August 1960 Electronics World

August 1960 Electronics World

August 1960 Electronics World Cover - RF Cafe  Table of Contents

Wax nostalgic about and learn from the history of early electronics. See articles from Electronics World, published May 1959 - December 1971. All copyrights hereby acknowledged.

Railroads have played a fairly major role in communications development. Beginning with carrying letter mail as cargo across vast distances much more quickly than horse-drawn coaches and even Pony Express, much of the early telegraph and then telephone electric lines were strung along rail lines. Doing so facilitated initial installation as well as maintenance since materials and personnel could be delivered quickly and conveniently. Many miles of old telegraph lines can still be seen lurking in the trees and weeds along tracks all over the country. Both telegraph and wireless communications were used to keep in contact with trains to establish location, weather condition, equipment status, Indian uprisings, to enable messaging to and from passengers, and to provide navigation instructions when the need arose. The world's first mobile radio broadcast took place on a train. This 1960 "Railroad Radio" article in Electronics World magazine reported on the state of the art at the time.

See also this 1944 End to End Communications for Trains article.

Railroad Radio

Railroad Radio, August 1960 Electronics World - RF CafeCommunications by radio is increasing the speed and efficiency with which our rail freight is handled.

Radio has not obsoleted the lantern. The lantern is still a very useful tool in railroad operations but radio has made life much more pleasant for railroad personnel and has contributed much to the more efficient operation of railroads. It is radio plus the diesel-electric locomotive which made it possible to haul longer trains, faster. It is in freight service, not in the operation of passenger trains, that railroads earn most of their income. And, it is in the operation of freight trains and the handling of freight cars that radio is of the greatest value to the railroads.

The most important application of radio in railroading is on freight trains to enable crews in the locomotive and the caboose to communicate with each other. Before radio, if the conductor wanted to stop the train he had no means of notifying the engineer. His only recourse was to open an air valve which applied the brakes. This often resulted in damage to the train. The engineer could communicate one way by tooting his whistle if the conductor could hear it. If you have ever ridden in a caboose, you can understand why this is an almost impossible feat.

Railroad yardmaster has complete communications - RF Cafe

This railroad yardmaster has complete communications at his finger tips. From his perch high above the Air Line Yard in Milwaukee, Wis., he can see freight yard operations. By operating switch keys on the console before him, he is able to talk with personnel on foot by means of two-way loudspeakers. He also has radiotelephone equipment for talking with crews on the engines. In addition, telephone lines are interconnected with the control console. At the left of the desk is a teletypewriter unit used to type out important messages. The over-all system thus represents an integration of radio, loudspeaker, telephone, and teletypewriter communications, all of which make for most efficient operation.

Today, the conductor picks up his microphone to tell the engineer to "high ball" (go ahead) as soon as the flagman is back on board after protecting a standing train. When the engineer has a mechanical problem, he too can pick up his microphone and tell the conductor of his troubles. Before radio, the conductor might have had to walk a mile or more to the head end of the train to talk things over with the engineer.

Now, when a defect such as a "hot box" occurs, the defective car can be set on a siding and the train can get under way in minutes compared to sometimes several hours in pre-radio days. Train crews are often provided with "walkie-talkies" which are extremely valuable in coordinating such tricky maneuvers. And the lucky flagman who has a walkie-talkie won't get left in the wilderness, which has often happened in the past. He can use his radio to tell the engineer to get ready to go but wait until he is actually on board.

Before radio, train crews were out of touch with the outside world except when they picked up written messages as they passed wayside towers. Radio has not obsoleted the written train order, but radio has certainly simplified the passage of vital information.

Railroad radio received its initial impetus when the Rock Island Line applied for a permit to experiment with two-way operation. This application, filed in April of 1944, was granted in February 1945. The first permanent authorization for railroad radio service was issued to the Denver & Rio Grande Western in February 1946. Permission for hump-yard communications was granted in August 1946 to the Baltimore & Ohio for its New Castle, Pa. yards.

Now thousands of miles of railroad trackage are covered by radio communication with base stations spaced 10 to 50 miles apart along the right-of-way. Train crews can now keep in touch with wayside tower operators and sometimes directly with the dispatcher many miles away. And, when wire lines are down, wayside towers can use their radio stations for communicating with each other.

Main Line Radio

A decade ago, radio was installed by the short but progressive South Shore Line which operates high-speed electric passenger service as well as freight trains between Chicago and South Bend. It was a newsworthy event because it was a case of the tail wagging the dog. This short-line railroad was the first in the United States to provide radio communication from one end of its system to the other. The installation was also significant because it was the first to use automatic relay stations to extend coverage. No wire lines were required for interconnecting the three base stations, as is ordinarily the case in such installations.

The example set by the South Shore Line probably had an effect on the thinking of some of the larger systems who saw how valuable radio could be to a railroad. Today, many of the major roads have extensive right-of-way radio systems. While these radio stations are often controlled locally or from a nearby telegraph tower, many roads use wire lines for interconnecting wayside radio stations with the dispatcher's office. Various techniques are used for selecting wayside radio stations individually from the dispatcher's office. The dispatcher may push a button or dial a number to select a radio station nearest the train with whose crew he wishes to communicate.

One of the first long-haul, right-of-way radio systems utilizing selective control of base stations was installed by the Northern Pacific Railway. The Erie was the first to install a radio system on the run between Chicago and New York.

Yard Communications

Yardmaster's tower in Barr Yard of B & O railroad - RF Cafe

Yardmaster's tower in Barr Yard of B & O railroad near Chicago with its intercom, radio, and complete paging facilities.

Train dispatcher can keep in touch with commuter trains - RF Cafe

The modern train dispatcher can keep in touch with commuter trains as well as profit-making freights with two-way radio.

Communication within a railroad marshaling yard before the electron era consisted of direct word of mouth, sometimes augmented by colored light signals. Electronics first made its appearance in the form of loudspeaker paging systems. This was one-way communication. However, two-way communication is required in order to affirm that an order has been received so telephones were used by yard personnel for replying.

Today's modern railroad yard is a maze of electronic gear. The one-way loudspeaker paging system is still there but personnel now reply through tiny hand-carried portable radio transmitters called "Dick Tracy" units by railroaders. The yardmaster switches on the paging loudspeakers in the specific area where he expects to locate the desired individual. Or, if he is apt to be almost anywhere, the yardmaster might page over the entire yard area.

When a yard employee hears his name called over the paging system, he merely holds the "Dick Tracy" unit near his lips and acknowledges the page. The feeble radio signal is picked up by a nearby remote radio receiver whose audio output is fed to the yard-master's office. Thus, a two-way conversation may be held, using audio to talk out and radio to talk in.

In addition to a paging system, the modern railroad yard is provided with a gigantic intercom system, some consisting of as many as 200 or more remote talk-back loudspeakers. These remote talk-back speakers are connected through underground cables to one or more control consoles, which resemble a pipe organ.

The yardmaster may page over the intercom system too. He flicks selector keys which group several talk-back speakers together, permitting low-level paging over selected areas. The paged person, in replying, merely steps up to the nearest talk-back speaker and pushes a signal button. This lights an identification lamp on the yardmaster's control console. The yardmaster then flicks the key associated with that lamp, switching that specific talk-back speaker into the circuit. The yard-master talks out by speaking into a microphone and stepping on a foot sw1tch under the console. To listen, he relieves the pressure on the foot switch.

The yardmaster can locate crews working in the yard area by flicking talk-back speaker selector keys on his console, one at a time, judging the location of the crew by listening to the incoming sounds.

There are several base radio stations in a typical, modern rail yard. One may be used for supervision of operations at the northbound hump, another at the southbound hump, a third for communicating with trains approaching or leaving the yard and still another for communicating with work crews and motor vehicles.

Generally, each of the base stations has its own control point since each is used in its own individual operation. However, in order to give the yardmaster complete control of all operations, the control console in one or more yard towers may also serve as an additional control point for all of the radio stations.

In the modern yard, the yardmaster has his own office on the top floor of a tall tower, not unlike an airport control tower, from which vantage point he can see the entire yard. He sits at a giant console which opens avenues of communication to yard personnel via a paging system, intercom system, two-way radio, and telephone circuits. Each group of paging speakers, individual talk-back speakers, base radio stations, and several telephone circuits all terminate in the console and may be activated by merely flicking the appropriate selector key.

Checking Cars

A few years ago, the car checker, who notes the numbers of all freight cars entering a yard, often had a miserable time trying to write down numbers in the rain or snow. Today, he carries a walkie-talkie with him and reads off the numbers which are taken down by a clerk inside a warm, cozy office, who sometimes tape records them for future reference. Here again, a separate base station is used for car checking so as not to clutter radio channels that are needed for other operations.

Equipment

Block diagram of a typical railroad yard communications system - RF Cafe

Block diagram of a typical railroad yard communications system.

Train engineers can keep in touch with wayside towers - RF Cafe

Train engineers can keep in touch with wayside towers and can summon aid when needed if they have two-way radio installation.

Radiotelephone handset being used by engineer of diesel-electric freight locomotive - RF Cafe

Radiotelephone handset being used by engineer of diesel-electric freight locomotive on the B & O's radio traffic control system.

Railroad radio equipment is packaged in single-unit as well as in three-unit assemblies. The single-unit combines transmitter, receiver, and power supply in a single enclosure. The three-unit sets consist of a separately housed transmitter, receiver, and power supply.

While electrically similar to mobile radio equipment for use in motor vehicles, railroad radio equipment has to be more ruggedly constructed. The audio power output of a vehicular radio unit is about one to two watts, whereas railroad radio units deliver from five to ten watts of audio, required to override the ambient noise encountered in cabooses in particular. The modern diesel locomotive, on the other hand, rides almost as smoothly as a Pullman car and is very quiet compared to the obsolete "iron horse."

Power Sources

The typical diesel locomotive is equipped with a 64-volt battery which is used as the source of power for radio equipment. Early locomotive installations used radio units designed for operation from 117-volts a.c. A rotary or vibrator type converter is used for converting the 64-volts d.c. to 117-volts a.c. Later, railroad radio units were introduced which contain a vibrator power supply that permits direct operation from the 64-volt battery, eliminating the need for a converter.

The Erie railroad equipped its cabooses with 32-volt batteries of the same type as used on passenger coaches. An axle-driven generator keeps the battery charged. Because of the high cost of 32-volt batteries, the Gulf, Mobile & Ohio Railroad experimented with 6-volt automobile batteries kept charged by an ordinary automotive generator which was driven by the wheels of the caboose. Later, most of the railroads settled on using a 12-volt truck battery and an axle-driven rectifier-alternator.

Passenger cars and baggage cars are generally provided with a 32-volt battery and an axle-driven generator. Some cars, however, are equipped with 64-volt or 110-volt batteries.

Communicating Frequencies

Most of the railroad radio systems in service operate in the 152-162 mc. band where 91 channels have been allocated to the Railroad Radio Service. Four channels are available in the 450-460 mc. band for use by the railroads and five channels are available in the 27 mc. band, but as this is written, so far there have been few takers. The reason for this is that the railroads prefer maximum interchangeability of equipment and do not want to mix brands or types. For example, a railroad that installs one brand of equipment generally sticks with the same brand when expanding.

While the railroads have been extremely fortunate in having so many channels assigned to them, the 152-162 mc. band does not offer a wholly satisfactory solution under all conditions. In some mountainous, densely wooded areas, for example, the range achieved when operating in the 152-162 mc. band is inadequate. Police radio systems operating in the same areas in the 25-50 mc. band enjoy much greater coverage. Sometimes such special installations are impractical because of cost and incompatibility with 152-162 me. systems in use on the rest of the railroad.

Some railroads are, however, making use of the 450-470 mc. band in freight pick-up and delivery operations. Trucks, operated by railroad subsidiaries, are equipped with conventional, vehicular-type 450 mc. mobile radio units for communicating with dispatchers and expediting the handling of freight that is less-than-carload-lot.

Maintenance

Most railroads buy their own radio equipment which is installed and maintained by railroad personnel. A few have leased equipment from telephone companies or independent distributors of radio equipment. While most railroads handle their own radio maintenance, even those with extensive communications departments sometimes farm out radio servicing in certain areas to independent service dealers.

Walkie-talkie radio permits freight train conductor to remain in constant touch - RF Cafe

The walkie-talkie radio permits freight train conductor to remain in constant touch with the train's crew when the train stops.

Radio equipment is seldom serviced on board a train. Instead, spare equipment is installed and the original equipment is brought into a shop for overhaul. Field servicing is generally limited to checking of the antenna system and electric power source.

Now that the railroads are making wide use of electronic devices, there are opportunities within the railroad industry for electronic technicians and engineers. The pay rate is good compared to many other industries but the biggest attraction is the security offered by the railroads. There is a pension plan which has deterred many from leaving railroad jobs for other fields. Those interested in railroad employment should get in touch with the superintendent of communications of the railroad with which they would like to become associated.

The Future

In the not-too-distant future, crews of terminal switching locomotives will be able to dial a number on an ordinary telephone dial when approaching a siding protected by a gate. When dialing, the radio transmitter in the locomotive sends out a combination of pulses which are picked up by a radio receiver near the closed gate. The pulses unlock a decoder which starts an automatic gate opening mechanism. The locomotive moves into the plant area through the open gate without first having to stop and wait until the gate is opened manually. Upon completion of the work in the plant area, the crew dials another number and the gate closes automatically.

Closed-circuit television is already being used in some yards, obviating the need for having a car checker stand out in the weather to read car numbers.

TV is also being used for inspecting the mechanical condition of cars as well as observing the over-all movements in a yard.

Further railroad automation is coming. Still unsolved is the problem of identifying freight cars automatically as they enter a yard. While push-buttons are used for controlling the movements of freight cars as they roll down the hump, it is still necessary to have human beings identify individual freight cars. This is often difficult when the number is almost, if not completely, illegible.

It has been suggested that cars be marked with colored strips in different combinations. The coded combinations are read by a photocell and the information is either stored or displayed by a computer. Another proposed system would provide for coding of cars with radio-active paints using a Geiger counter for reading the numbers.

The use of microwave systems by railroads is expected to expand materially. Much of the open-wire pole line plant operated by the railroads, about 250,000 miles of lines, will require re-placement or rehabilitation. Maximum use of these wire lines is being made by many railroads which have installed modern telephone and telegraph carrier systems. One pair of wires, equipped with a modern carrier system, can handle up to a dozen telephone conversations simultaneously. But, even this is not sufficient to accommodate the growing need for communications. Hence, microwave systems which can handle up to 200 voice channels offer freedom from communications congestion.

It is the transistor, however, which is expected to revolutionize railroad communications for the second time since World War II. Transistorized telephone carrier and voice repeaters, which can be operated from batteries, can be installed in remote locations where reliable utility power is not available. Even the smallest yards and some sidings where electric power is not available can be equipped with paging and intercom systems utilizing battery-operated transistorized amplifiers.

Partially transistorized railroad equipment is already available. Transistors are being used in audio output stages and in lieu of vibrators in power supplies. But it is the all-transistorized railroad radio that is being awaited by the industry. Imagine a caboose radio the size of a portable typewriter, perhaps even smaller, which will operate from a pair of lantern batteries or even solar cells. The vibrator, axle-drive assembly, storage battery, and charging generator will then be only memories. Based on observations of the present rate of progress of the electronics art, the all-transistorized railroad radio is not far away.

 

 

Posted January 5, 2023

Axiom Test Equipment - RF Cafe

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RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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