Stacks At The Stacks. On March 9, 2019, Norfolk Southern 3366 (née-CR 6421, SD40-2, EMD, 9/1977) was passing through CP Bethlehem in Bethlehem, Pennsylvania while working H76 with a cut of intermodal containers, also known as "stacks". In the background, the former Bethlehem Steel Factory, now known as the SteelStacks, looms over the city. From 1857 until its closure in 2003, this facility was one of the largest steel producing companies. Today, SteelStacks is an arts and entertainment district that stabilizes a portion of the remaining industrial facility.