It's not obvious unless you see a full passenger train schedule or employee timetable that
the BLACK GOLD did a shuffle between Ft. Worth and Dallas which did not involve a combination
of trains at Irving.
Example: The BLACK GOLD would leave Ft. Worth and head all the way over to Dallas on the
Rock Island's line. There it would take on passengers and then depart for Irving, Sherman, and
Southbound the BLACK GOLD would stop at Dallas before heading over to Ft. Worth.
Cotton Belt passenger trains did a similar shuffle on its own line when Ft. Worth was still served.