Vintage Circa 1930s Ceiling Light Fixture- Railroad Or Ship?

The Fixture is hinged for easy light bulb replacement and the splitframeisheldtogetherwithasinglebrassthumbscrew,  and as you can see in the photo, there is a channel shaped cushion that snugly hugs the base of the upper thick, ribbed, globe.

I originally thought it was a gasket to prevent moisture from entering the inside of the fixture, but there is a 1/4" gap between the 2 ends of the channel cushion where they meet,  and this appears to be by design.

In addition,  the material is not soft and pliable as would likely be the case for weatherstripping.

Plus, the top of the bottom frame has relatively large slots in the casting which would allow any moisture to safely drain away to the outside of the bottom thick glass globe.

Per the photo, you can see that the unit hangs from a very heavy, solid brass swivel that only allows a limited amount of travel. In fact,  the photo shows the maximum amount of angle that the fixture is allowed to swing or sway.

This feature had me scratching my head about what type of circumstances would actually benefit from the very limited amount of travel,  and eventually it dawned on me that either a train coach or perhaps a ship would have a need for a limited ability to sway, yet not enough to allow a more violent swinging of the fixture..

I completely dismantled the fixture in order to thoroughly clean the glass and nonferrous heavy cast frame.

The Item Specifics lists the frame as Pewter, but I have no proof of this. However, it sure has the characteristics of Pewter in regards to the thickness, grainy texture, and silvery color beneath the black semigloss paint.

To be clear, the original paint was chipped in several places- mostly on the edges of the fixture in several places and they certainly degraded the stately beauty of the fixture so I was fortunate to find a nearly identical color and sheen and repainted it to restore it's original allure.

The original light socket was replaced some time in the past with a MCM UL Approved socket and wiring.

When mounted, it's about 17" from the ceiling to the very bottom, and about 7 1/2" wide at it's widest point of the scalloped frame.