Early Grade Crossing Signage / Signaling Question

[NW Mailing List]

Good morning. I’ve attached four screenshots of a grade crossing sign / warning I’d like to know more about. The post has an instrument box on it about chest high, the circular warning is worded “Railroad Crossing” around the perimeter, and “Danger” on the crossbar. The photos are roughly in chronological order, and the the latest two (~1925, 1932) have cross bucks in the photo, which are perhaps superseding the style in question. 

I’m especially curious bout the cylindrical device at the top - is this an audible alarm?  The third photo has a cable running to the adjacent tower. Two of the other three also have watchman’s towers at the same crossing, which suggests they were controlled remotely. 

Thanks!

Credits / other detail 
Circleville Ohio @ S. Washington Street, ca. 1900, collection of Robert Good
Unknown location, Virginia. Va Tech collection
Circleville, Ohio @ W. Mill, ca 1925, Matt Goodman collection (via Pickaway County Historical and Genealogical Library)
Circleville Ohio @ W. Main Street, 1932, collection of Robert Good

Matt Goodman
Columbus, Ohio, US

  
 

 
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