[GreenKeys] unusual cover, or not?

[dmm at lemur.com]

In the Library of Congress' Prints and Photographs collection,
there are two similar images depicting "Switch lists coming in by 
teletype to the hump office at a Chicago and Northwestern railroad 
yard, Chicago, Ill."

Each shows a person holding what is clearly Teletype printout
on top of a case or cabinet of (to me) unusual construction.

http://www.loc.gov/pictures/item/fsa1992000672/PP/

http://www.loc.gov/pictures/item/owi2001010044/PP/

Are these in fact Teletype covers/cabinets/whatever?
They look as if they might have heavy sound insulation.
Or are they simply furniture?   
BTW, if you take the time to download the highest-resolution
TIFF of the color image (132 Meg), you can read the lists.

The Illinois Central, btw, looked like this at the same time:

http://www.loc.gov/pictures/item/owi2001013088/PP/

Regards,
David M.
===
Dr. David M. MacMillan * dmm at lemur.com * www.lemur.com & www.CircuitousRoot.com

   First do no harm. (Primum non nocere.)
       - possibly Galen; see also Hippocrates (Epidemics, Bk. I, Sect. XI.)
   The first rule of intelligent tinkering is to save all the parts.
       - Paul Ehrlich (1854-1915); Aldo Leopold