Norton/Pete... I take it the Jack Delano pic was most likely taken in the 40s, during war time. Notice the "cowling" over the lead unit headlight. Only need for these would be to reduce upward glare and long distance overhead detection.
Yes, The date is the early '40s. Jack worked initially for the Farm Security Administration (FSA) which later morphed into the Office of War Information (OWI). The FSA charged a group of photographers to go out during the depression and document the misery it was producing in the country to convince Congress to act. As the war began they were sent out to document the war effort at home.
To see their work go to the Library of Congress site and search on FSA/OWI. The majority of railroad images were taken by Jack Delano and have made it on sites like Shorpy.
Warning, you can spend days pouring over the photographs at the Library of Congress.