Like with barcodes, they just allocate more top-level identifiers as part of the company G1 code. For eg. Textainer are also CLHU, AMFU, GAEU, WCIU, XINU, AMZU,

Like with barcodes, they just allocate more top-level identifiers as part of the company G1 code. For eg. Textainer are also CLHU, AMFU, GAEU, WCIU, XINU, AMZU, GATU, etc. amongst many others. That is why they also color-code the containers and put their logos on them. The code is ISO 6346[1] and was defined a long, long time ago and didn't scale very well (or you could say that is scaled perfectly well - nobody imagined that 5-6 companies would control most of shipping). The container ID part, ie. the '22G1', that the article mentions actually isn't part of the ISO code and is usually printed below the ISO code. So the container needs to be identified between the top-level company ID and the 6-digit container ID, hence lots of top-level ID's for the big companies. The whole topic of containerization and how the world came to agree on standards is interesting and has a parallel in web standards[3]. You can ship a container from Canada to Niger and know that when it gets off a ship they will have a crane to pick it up, a barcode to scan and lookup its contents, the right power plugs to power it if it is refrigerated, a way to identify the destination, owner, etc. Fascinating stuff. [1] http://en.wikipedia.org/wiki/ISO_6346 http://en.wikipedia.org/wiki/ISO_6346 [2] http://www.containerking.co.uk/buy-cabins/images/Shipping%20Container%20001.jpg http://www.containerking.co.uk/buy-cabins/images/Shipping%20... <- see the '22G1' is printed below the ID [3] http://en.wikipedia.org/wiki/Containerization http://en.wikipedia.org/wiki/Containerization