What is on this roof?

[Chris333]

on a lark, I asked ChatGPT. 
I asked it:
what is the device mounted on the roof of the Hundington and broad top mountain railroad station in this picture?

Here's what it said (I'm not sure I believe it):

From the photo, the device on the roof appears to be a rotating roof ventilator (often called a turbine vent or rotary ventilator) rather than a signal or communications device.

The key clues are:

It is mounted on a short roof curb near the ridge.
The visible circular opening with curved internal vanes is characteristic of an early rotary ventilator.
It has a square hood or cap above it to keep rain out while allowing air to escape.

Railroad depots of the late 19th and early 20th centuries commonly used these to ventilate:

waiting rooms,
ticket offices,
baggage rooms, and
especially rooms heated by coal or wood stoves.

As warm air rose, the wind would spin the ventilator (or simply create suction in some designs), drawing hot, smoky air out of the building.

What it probably is not

It doesn't resemble:

a train-order signal,
a whistle,
a bell,
a lightning rod,
a siren, or
a telegraph device.

Those were mounted and shaped quite differently.

One interesting possibility

This ventilator appears to be an older "Globe" or "Flettner"-style rotary ventilator that was popular on railroad buildings around 1890–1930. Many H&BT stations had coal stoves, making roof ventilation important during winter operations.

Thanks for trying.

I never used Chat GPT, but how can it tell you something as a fact and not tell you where it gets it's information?

Now another guy has told me it is a clock "for certain". *if* it was a clock shouldn't it be rotated 90 degrees and have a face on each side for train to see it?

I guess in the end I can just leave it off, but I wanna know what it is 

[Lemosteam]

So looking at the item, there is either a conduit or a rotating device through the roof and down the wall. could that be some form of lever activator that would swing the round plate out, for some type of signal, similar to a Semaphore that would be visible to an engine crew in either direction?

[thomasjmdavis]

I'll agree with chatGPT that the devices vaguely resemble Globe or Flettner ventilators, but only in so far as they are round.  Those ventilators, generally speaking, exhaust air through a roof or through a wall, not sitting in a box on the lower edge of the roof.

And... not to be argumentative, but the photos do not show it near the ridge of the roof.  In fact, the device sits past the edge of the wall- and all the photos I saw confirmed Lemosteam's observation about the pipe or conduit or rod coming down on the wall just below.

And... there is no evidence of a duct coming from the inside of the building, either behind it or under it- so I don't see how it could be a ventilator.

Maybe a really ornate flag for flag-stops?  Turn it in the direction of the oncoming train?  It doesn't appear on any of the larger H&BT stations that I could find in the photos of.
https://www.west2k.com/pastations/huntingdon.shtml

I note that several of the stations are listed as museums.  Perhaps one of them can provide a definitive answer (and/or a diagram or blueprint ID'ing the part)

[Kentuckian]

I believe that it is a fan manufactured by the B.F. Sturtevant Company. I assume it was an attempt to blow smoke and cinders from the exhaust stack away from the platform? The conduit is an electrical conduit for the power. It was probably added after the station was built. This is all my hypothesis.

[Sokramiketes]

Given how thin it is, and its location on the roof, I agree there's no way it's providing ventilation to the interior of the station.

I like the clock angle.  That feels more correct? 

[Maletrain]

It doesn't make sense to put a clock in that position, because nobody on the platform would be able to read it.  To read it, you would need to be on the other side of the tracks.

[OldEastRR]

You can muddle your way thru this website.

https://www.bfsturtevant.com/survivors.html

This company looks like the best bet to have made the thing. Plus at the bottom of the p[age are mfgrs from other countries.

[StarCruiser]

Could be a variant of this one:

https://www.bfsturtevant.com/Images/Products/Survivors/Surv138.jpg

Wind-O-Vane

There were apparently several variants but, they were mainly intended for mounting in a window - hence the name.

[nickelplate759]

The more I think about it, the less I think it has anything to do with ventilation.  I'm quire sure that ChatGPT was just making s**t up.  No one would put a ventilator in that spot more than once, certainly not make it a standard part of their station.   Can't imagine it would do much when it snows, for example.

I'm going with some kind of signaling device.  Possibly manually controlled, and the "conduit" down to the platform is probably the actuator.

[Sokramiketes]

It doesn't make sense to put a clock in that position, because nobody on the platform would be able to read it.  To read it, you would need to be on the other side of the tracks.

That might be part of why it was a fad and didn't last long?  I'm picturing someone in small towns going "we should have a town clock on our stations like the big cities" and maybe it was visible across the street. 

[k27463]

Jasdon:  Maybe the disc rotates on a vertical axis?  As show, it would be "no orders".  Turned 90 degrees, it would be "stop for orders".

I would think a less obstructive frame would be better, but it's the only thing I can think of.

I'm 90% sure this is what it is -- note that on all of them there is a vertical rod underneath which likely would be used to rotate the signal.

The conduit could be to hold a light bulb for night operations.