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Why Do Engines Still Have Signal Air Lines?

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  • Member since
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Posted by SD70Dude on Saturday, January 8, 2022 9:03 PM

The supplementary air supply is still used for water raising.  Not sure if it has any other uses.  

I agree that radios have long since superseded the functionality of the air signal line, but in Canada the air signal rules remained in the UCOR until it was replaced by the CROR, and I've seen video of crews using the air signal line in the late 1980s.

A lot of freight units used to have the supplementary air line as well, and at least some had cab whistles, like our ex-CN F3A.  Some of our older power still has the lines but the hoses have been removed and the lines capped.  

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-an Articulate Malcontent

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Why Do Engines Still Have Signal Air Lines?
Posted by gmpullman on Saturday, January 8, 2022 7:48 PM

Admittedly, I haven't kept pace with "modern times" on Passenger Railroads. That said, I came across this photo of an Acela power car with her mouth open By George Hamlin. 

 16-3766 by George  Hamlin, on Flickr

Then the thought occurred to me when I saw the glad-hand for the air signal, or communication whistle line there it made me wonder why this anachronism is still being provided on engines and/or cars in passenger service.

I'm pretty sure I remember communicating whistle valves on the Amfleet cars. Never recall seeing them used, though. Were they installed on the Superliners? Signal lines, yes — but were they piped to actuating valves?

Then on to the Acelas and ACS 64s, do they actually have cab signal whistles? Was the signal line repurposed for some other use besides the communication whistle?

I would think with the proliferation of radios, PTC, digital intercoms between cars, etc. that the signal whistle would have gone the way of the dodo.

One of my favorite passenger-riding memories was watching the conductor's use of the communicating whistle and, if standing near the cab, you could sure hear that peanut whistle inside.

Just curious. 

Regards, Ed

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