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Discussion Boards => HO => Topic started by: OkieRick on July 06, 2009, 10:53:34 PM

Title: Broadway EMD F7A/B - Antennae on Loco
Post by: OkieRick on July 06, 2009, 10:53:34 PM
I was browsing the Broadway website and ran across this F7 unit with an antennae.  What's is for?



                (http://i26.tinypic.com/11h3s05.jpg)


I couldn't locate any photos of loco like it, PRR or other.

Rick
Title: Re: Broadway EMD F7A/B - Antennae on Loco
Post by: Tim on July 06, 2009, 11:18:22 PM
Rick

It is a PRR train phone antenna.
They predate radio like is now used.

It was an inductive system, not radio.

It didn't work system wide like radio, only in areas
near major terminals of junctions.

Tim Anders
Souderton, PA
Title: Re: Broadway EMD F7A/B - Antennae on Loco
Post by: jward on July 06, 2009, 11:31:40 PM
it was similar in concept to radio, except that it used the wires on the trackside pole lines to carry the signal instead of radio waves. the transmitter was a pair of large coils that transmitted the signal to the pole line by induction, the long antenna received the signal from the pole line. on the pennsy, it was used on the mainlines as well as around major terminals.

pennsy was the major user, but i believe kansas city southern also used the system. it was superceded by radio in the 1960s, on pennsy only units built before 1963 had the antennae. for the most part, the antennae were removed before the penn central merger of 1968, although there were a few instances of locomotives having antennae into the early 1970s.

a full explanation of the system can be found here:
http://kc.pennsyrr.com/faqs/trainphone.php