Elizabeth, every container that moves must be placed onto a chassis (wheels). When an import loaded arriving container is off-loaded from the ship, it is typically placed (without wheels) onto the dock yard stack of containers. The party receiving the container (consignee) is notified that the container is now available and they typically make arrangements with a local trucker/drayage company to pickup the available loaded container. The trucker usually must obtain a chassis from one of the pools (mentioned in my earlier comment) and go to the shipyard dock to pickup the available load where the shipyard places the loaded container onto the chassis the trucker brought into the yard for pickup. The loaded container is then moved from the shipyard to the local consignee for delivery. After it is delivered and unloaded, the now empty container (still on the chassis) must be returned to the ship dock and then the chassis returned to the pool. However, empty containers are piling up in the ports (https://www.reuters.com/business/retail-consumer/port-los-angeles-import-backups-ease-empty-containers-pile-up-2021-11-16/) impeding the return of newly empty containers, and thus you see the trucking companies reporting, "Our chassis are sitting under these empties that have nowhere to go." and "Not because we have capacity issues but we cannot return the empties for days. Empties sit on our chassis in our yard(s) accruing charges." So chassis availability to pickup loaded containers from the ports is currently very unreliable. It is a complicated issue and what I've described above is a generalized explanation. Hope this helps.
Vitor, allow me in this conversation. I also have been in the industry and you have done a great job describing overall operations. A piece of the container shipping puzzle you didn't cover was chassis, and these are a key ingredient to the operations. Since there are proprietary pools, third party pools, and grey pools, this adds another degree of complexity. Some trucking companies in LA claim that chassis availability is one of the primary issues: no chassis, then no container move in/out of the port. Thanks for writing your article.
A tragic yet uplifting story that I'm grateful to now know. How many more heroic examples there must be! Thanks for sharing it. Like you, I'm also not eager to skip meals but am inspired to honor Vavilov.