>Is anyone aware of museum exhibits that have covered the subject of ...
>black railroad labor?
 
Tonight, Ted Kornweibel presented an hour-long slide show and lecture on
your subject at the California State Railroad Museum.  He is a professor at
San Diego State and the superintendent of restoration at the San Diego
Railroad Museum.  He's not on the net but his office phone is (619)
595-3030.  Excellent program!
 
>...are there any museums with collections of railroad photographs,
>advertisements, or art?
 
The CSRM has zillions of photographs, negatives, advertisements and art.
Wanna do some cataloging?  CSRM isn't on the net either.  The library voice
phone is (916) 323-8073 and staffed 1:00 pm to 5:00 pm Tuesday thru
Saturday.  The mailing address is:  111 "I" Street, Sacramento, CA  95814.