The answer appears to be yes, particularly on lower frequencies (with larger wavelengths). The tracks act as a wave guide.
I was looking at a house that was near tracks (although it's difficult where I live NOT to be near tracks), and was wondering. It remains to be seen (if I ever do try it) how well Part 15 radio waves would do.
Yes! Many years back there had been discussed here.. can't quite remember exactly what it was about.
But back in the 1940s it was actually experimented doing it some, Halstead had actually been involved with it.. I think it had also been used to activate warning lights or something early on, I don't remember the details, but do recall reading about it. Carrier on the rails were a doable method but there were some problems involved with it. Not sure if I saved those articles, will dig around and see.
I think railway tracks would make a great antenna.
Interestingly there is a recent (2014) patent to do just that https://patents.google.com/patent/US9840260B2/en
Of course the reception area would only be within in a few hundred feet of the tracks (as expected with carrier-current), but for a reasonable ample distance down the tracks, so a low power signal could feasibly cover a fair distance like a few miles on either side of those tracks just as use to be at Disney World, LAX, and various highways and bridges. It's the same concept.
Coincidentally, there happens to be a movement right now going on to convert abandoned railways to some kind of nature trails https://www.outsideonline.com/culture/books-media/rails-to-trails-doc/ While the agenda doesn't mention it, carrier current radio could certainly be incorporated into the idea
Well, maybe we hadn't discussed it before, can't find any past topics addressing it (though it seems like we did a long time ago).
However, they did do something like that in the 1940s, for Trainphone operations: https://en.wikipedia.org/wiki/Trainphone
Trainphone was the Pennsylvania Railroad's system for voice communication between crews on moving trains, dispatchers, and tower operators. It was also used by the Kansas City Southern, and to a 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, .... The trainphone system was first tested 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.
I can see(or at least speculate) how it might be effective to broadcast AM to houses near train tracks, but it seems it might actually be more effective to cover the same area using 15.219 free-radiate method.
@ArtisianRadio Interesting topic!
I was actually thinking that a free radiating AM signal might follow those tracks, much like AM can get into power lines and follow them.
Well that's not what I was thinking, but it is an even more intriguing, My guess is the same as yours, it probably would, but for how far?
So I just asked Google AI can railroad tracks indirectly increase range of low power am signals? and it replied with what sounds like a reasonable answer, it begins:
Yes, railroad tracks can indirectly increase the range of low-power AM signals, but not reliably. The enhancement is a byproduct of how AM radio waves interact with the environment, particularly through improved grounding, signal "ducting," and reflection. This effect is inconsistent and depends heavily on factors like the transmitter's location relative to the tracks and the surrounding terrain.
How railroad tracks can boost AM signals
Acting as a ground plane. AM radio signals, especially in the long-wave band, travel primarily via "groundwave" propagation during the day. This form of transmission requires a good ground or "counterpoise" to function efficiently. The extensive, grounded metal structure of railroad tracks can act as an effective artificial ground plane, increasing the efficiency of an AM signal transmitted nearby. A more efficient antenna system can transmit and receive signals over a longer distance.
It continues with greater detail from there vis the link above.
Of course the reception area would only be within in a few hundred feet of the tracks (as expected with carrier-current), but for a reasonable ample distance down the tracks, so a low power signal could feasibly cover a fair distance like a few miles on either side of those tracks just as use to be at Disney World, LAX, and various highways and bridges. It's the same concept.
Coincidentally, there happens to be a movement right now going on to convert abandoned railways to some kind of nature trails https://www.outsideonline.com/culture/books-media/rails-to-trails-doc/ While the agenda doesn't mention it, carrier current radio could certainly be incorporated into the idea
Katy Trail runs clear across Missouri, friend. It's been around for nearly 30 years! It's a fitness and biking trail on the old Katy Railroad right of way. Real nice trail. When they were busting it up back in 1986 I snagged a piece of 100 lb. demolitioned rail measuring 18 inches near Jefferson City, MO.
@centinel Ah.. only skimmed the article myself, it caught my attention because we had been talking about train tracks. Upon looking at it again I see what they are launching is a documentary about the 60 year plight to make those trails what they are today... I didn't know about any of that. Pretty cool.
@artisan-radio Might find this interesting...
From the Defense Technical Information Center (DTIC)
https://apps.dtic.mil/sti/citations/AD0822478
USE OF RAILROAD TRACKS FOR CARRIER TELEPHONY AND AS LONG-WIRE ANTENNAS FOR TRANSMISSION OF LONG-WAVE RADIO SIGNALS.
ARMY ELECTRONICS COMMAND FORT MONMOUTH NJ
Report Date:
1967 Jun 01
Abstract:
Investigations were made of the performance characteristics of manmade structures i.e., railroad tracks, buried pipes, and sewer lines for VLF signal transmission. Electromagnetic coupling devices designed for signal transmission are discussed. Signal transmissions over a distance of up to 15 miles were achieved with a consumption of less than 10 watts nominal 48 kHz transmitted power. A single ferrite loop was used as a receiver. Impulses picked up along fences and other metal structures denote signal re-radiation by railroad track. Results of these experiments indicate that railroad tracks act as signal ducts, and possibly, long-wave antennas.
Disc:laimers
The findings in this report are not to be construed as an official Department of the Army position, unless so designated by other authorized documents. .. ...
______
Direct link to the actual pdf' 30 pages: https://apps.dtic.mil/sti/trecms/pdf/AD0822478.pdf