Great, rare photos. Looks like the train is working the former Tribune spur that ran alongside the lower, north end of the building, using the track section near Columbus Drive as a tail track. I would place the photos sometime between 1977 and 1983 since in 1984 the Tribune relocated its printing presses to the new Freedom Center plant on Chicago Avenue at the river. Another clue is the Pontiac Pariseienne car in the background. GM introduced that body style in 1977 on their full-size cars.
