There are sites that offer templates for printing containers out of cardboard perhaps you could print out the template for measuring too.
Joe Staten Island West
Get your other needed (lesseer) dimensions off an existing model. Or even scale them off a photo. Photos of containers are kind of common online.
Once you have the major dimensions, the rest are kind of simple. I will note that not all model containers have the correct OVERALL dimensions. But you do. Now.
Ed
I have found information like that elsewhere, though that is a a quite well done infographic. What I have had trouble finding are the more intricate details, such as the size of that top piece of box section and the lower I beam thing.
Lost in the snow
High cubes are a foot taller
48's on up are 6" wider
Exterior and interior dimensions
A webpage about containers
http://www.matts-place.com/intermodal/part1/sea_containers1.htm
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
I am looking for exact dimensions of intermodal boxes, mainly 40 footers. I want to attempt to scratch build some, so I would need dimensions for the box section across the top, ect. If anyone knows of any diagrams, or data sheets that would have that kind of information i would greatly appreciate it.
On a side note, I am looking for detail photos of MAXI I cars. I have found some but not what you would call a plethora.
Merry Christmas, hope you are all taking it easy.