All,

Today during my model RR clubs open house, I was approached by someone wanting to get rid of a headlight lens from a steam locomotive. He found it in a flee market near Roanoke, VA. There used to be a piece of paper taped to it describing what it came off of, and he swears it was of N&W heritage.

Attached is an image of it. Measurments are 10.5" x .75"

Can anyone confirm that this is even a headlight lens from a steam locomotive? seems small to me... Thickness is correct. My first thought was a J or K class? I still think its too small.

Jason, that item looks like the right size for a steam locomotive headlight window, or front glass piece.

From the photo it appears flat (front and rear surfaces parallel and flat).

The term "Lens" usually means a curved optical piece that magnifys an image. In most headlight applications (locomotives, cars, planes, ships, etc.) a curved reflector (mirror) is placed behind the actual light source and focuses the light into a beam.

The window acts to protect the light bulb and reflector from stones, rain, insects, etc. They are usually fairly thick (~ 1/2 to 1 inch) to make up for the fragile nature of the glass material. Automotive headlight windows are thin now simply because the plastic materials are so tough when compared to glass.

I am speaking as an optical lens designer, the old steam railroaders may have used the generic term "lens" for that item, we would call it a window.

It could be from a steam or diesel locomotive headlight, or a searchlight on a ship, etc. There is probably no way to know for sure. There are many applications that use similar sizes, many exterior lighting fixtures had thick glass just so folks couldn't knock out a light with a well thrown stone. It looks a little thick to be a window for a building, unless the building was in a really bad neighborhood Ha Ha.

Cheers, Kevin.

Kevin,

Thanks for the info! The guy swore it was off a steam engine, but looking at it, im thinking an F serise diesel maybe? if RR at all.

I did find one faint marking on it.
HERCULITE
PLATE GLASS
45 6

Could also be a port hole off an old ship. Within the size range and about the right thickness. We used to turn these into telescope mirrors.

Bob

.

I believe it is a piece of high pressure glass from a pressure testing vessel I've seen one like it before, as a glass cover for a large steam pressure gauge. I believe it's too thick and heavy for a locomotive headlight or Diesel body port hole window. It is a nice piece of glass for a special purpose, but I doubt it is directly related to a mainline locomotive.