I’m dabbling in N while clearing out enough room for the HO layout. I have 10 well cars to fill on the cheap. Considering the large number of containers needed to model contemporary operations, I assume N scalers know of some low cost options. I’m getting close to just using wooden blocks. I am in shock over how much they can cost and can’t justify it for a temporary layout.
I would use Microsoft Paint on my computer and design a model, or import photos or other images. Scale it to the size you want and print the whole thing on card stock. If you “attach” the top, sides, bottom and ends, you can just cut out the model, fold it, glue the edges together and you have your container. If you need the weight, you can use that wood block and glue your images to it.
It wouldn’t surprise me if there are already images out there on the www for you to download, scale and print. But, I’m stuck in the Transition Era so I don’t know much about those things.
You know, this is interesting – there is a perhaps slight but nonetheless very detectable increase in interest in returning to paper as a model building material.