Trainphone
Encyclopedia
Trainphone was the Pennsylvania Railroad
's system for voice communication between train crews on moving trains and with dispatchers, tower operators and similar. It was also used by the Kansas City Southern, and to some lesser extent on the Duluth, Missabe & Iron Range
. It did not use radio, but rather electromagnetic induction
. Railroads did not own any radio frequencies
at the time, and the PRR's busy network found the previous methods (passing a physical paper message, or requiring a train to stop to pick up orders) insufficient. The trainphone system was first trialled in 1936 and perfected by 1943.
The system used the track
itself, or lineside telegraph wires, as the "shore" transmitter. The trainphone signal — low frequency current in the hundreds of kilohertz — was passed through the track or wires and induced a corresponding current in the locomotive or car's receiving antenna. The range was only a hundred feet or so, but this was sufficient.
Mobile trainphone antennas took the form of long, handrail-looking structures atop the tender of steam locomotive
s, atop the bodies of diesel locomotive
s, or running the entire length of a cabin car (PRR-ese for caboose
).
The engineer or other crew member would talk through a regular-looking telephone handset. An attention loudspeaker was also installed, but it was easier to hear the messages with the handset.
The biggest problem with the trainphone system was that it could not work in electrified zones, because of interference from the electric supply and electrical equipment on the locomotive. Since the electrified zones were among the PRR's busiest, this was a serious disadvantage.
The trainphone system was abandoned in the 1960s as radio took over.
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
's system for voice communication between train crews on moving trains and with dispatchers, tower operators and similar. It was also used by the Kansas City Southern, and to some lesser extent on the Duluth, Missabe & Iron Range
Duluth, Missabe and Iron Range Railway
The Duluth, Missabe and Iron Range Railway is a railroad operating in northern Minnesota and Wisconsin that hauls iron ore and later taconite to the Great Lakes ports of Duluth and Two Harbors, Minnesota...
. It did not use radio, but rather electromagnetic induction
Electromagnetic induction
Electromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids....
. Railroads did not own any radio frequencies
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
at the time, and the PRR's busy network found the previous methods (passing a physical paper message, or requiring a train to stop to pick up orders) insufficient. The trainphone system was first trialled in 1936 and perfected by 1943.
The system used the track
Rail tracks
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...
itself, or lineside telegraph wires, as the "shore" transmitter. The trainphone signal — low frequency current in the hundreds of kilohertz — was passed through the track or wires and induced a corresponding current in the locomotive or car's receiving antenna. The range was only a hundred feet or so, but this was sufficient.
Mobile trainphone antennas took the form of long, handrail-looking structures atop the tender of steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
s, atop the bodies of diesel locomotive
Diesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
s, or running the entire length of a cabin car (PRR-ese for caboose
Caboose
A caboose is a manned North American rail transport vehicle coupled at the end of a freight train. Although cabooses were once used on nearly every freight train, their use has declined and they are seldom seen on trains, except on locals and smaller railroads.-Function:The caboose provided the...
).
The engineer or other crew member would talk through a regular-looking telephone handset. An attention loudspeaker was also installed, but it was easier to hear the messages with the handset.
The biggest problem with the trainphone system was that it could not work in electrified zones, because of interference from the electric supply and electrical equipment on the locomotive. Since the electrified zones were among the PRR's busiest, this was a serious disadvantage.
The trainphone system was abandoned in the 1960s as radio took over.