Thinking K-Line made some once upon a time that worked with their containers from their intermodal cars. Not sure how easy it would be to find them. Check Nicholas Smith Trains which was once a K-Line superstore. http://www.legacykline.com/app...mp;p_oem_sku=K-8600S
Long before AtlasO was making their beautiful intermodal sets, the K-Line ones were die-cast and pretty impressive....I have the 5 car spline set and a couple of their stand alone thrall cars.