I noticed the same thing yesterday (12/2/08) while passing by the North Avenue yard around noon. The yard did look very empty.
Also it was a Tuesday and the Chicago Terminal locomotive was still parked at the end of the spur by the yard office with two UP locomotives blocking its path. Normally CTR goes out on Tuesdays and Thursdays.
Most of CTR\'s business is tied to economic cycles and it is probably taking a hit now. Their four remaining customers are all tied to the steel products, scrap metal, and construction businesses-all of which have taken hits from the global slowdown.