Dave, the first several cars are Atlas O Gunderson Maxi-IV, loaded with Atlas O 53' containers. The last several sets of stacks are custom built MTH 5-car articulated Gunderson stack sets, loaded with Atlas O 20' and 40' containers, with some 53's on top. All have Atlas O 2 rail trucks, Kadee 740 couplers.
Thanks also Dave and Steve for the comments!