make clones then you need to edit the config file in explorer for the cars to accept the containers...you also need to do some editing in ccp so the cars accept the containers..be aware if you want double stacks you will have a gap between the containers..i only use my clones for ocemy's yard and single stack..my solution was to make four clones 1 for 20 ft. empties 1 for 40 ft. empties and 1 each for 20 ft. and 40 ft. loaded. this works for my use for spawning A I trains. others may have another workaround for you