For railroad experts, contact your local hobby shop and ask about a
model railroad club nearby.  I swear, these people know more about
trains than you'll want to know.  My guess would be that they are
usually more knowledgable than the railroads, themselves.
 
Good Luck,
Chuck Coker
[log in to unmask]
 
P.S.  In just about ANY area, I find that enthusiastic "amatuers" are
better sources than "professionals".  I'm not going to say what line
of work I'm in (but it's not trains).  ;-)