I want to see a picture and description of a US Postal Service mail
bag used to carry registed mail on the railroad between Boston, MA and
New London, CT during World War II.

len1943...

Here's a few links for the sake of nostalgia, though none
of them were taken from the railroad between the cities you
noted, and none specify registered mail as the contents.
I just thought maybe you'd recognize one from a distance
in the photos, if there were one. If there is a picture
as specific as you'd like, you might find it where these
came from - The American Memory at the Library of Congress:
http://memory.loc.gov/ammem/collections/finder.html

Here are most of the railroad mailbags that I could find
from that time period:

http://memory.loc.gov/cgi-bin/query/I?fsaall:59:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8b26135:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:56:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8b26138:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:49:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8a28677:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:20:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8b14714:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:19:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8b14716:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:18:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8c30449:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:17:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8c30448:@@@

http://memory.loc.gov/cgi-bin/query/I?fsaall:16:./temp/~ammem_44pp::displayType=1:m856sd=fsa:m856sf=8c30450:@@@

len1943...

Fellow researchers alerted me to the fact that the above links
weren't working, due to the temporary nature of the search results.
If you go to the following page and enter the terms "mail bag",
without the parentheses, you can duplicate the search results
I used to locate the pictures. Some results will be unrelated to
mail bags or railroads, but you can browse through them, as I did.
http://memory.loc.gov/cgi-bin/query/r?ammem/collections:@FIELD(SUBJ+@band(Railroads++United+States++1930+1950+)):heading=Subjects%3a+Railroads--United+States--1930-1950.