A very important freight car type for railroads of all nations trading globally are those transporting containers. Depictions of this freight started appearing about 20 years ago in the Marklin Z line-up with several sets for DB (82360: 1997-1999), DB AG (82367: 1999-2001) and SBB (82368: 2000-2001); individual cars and train sets with this freight appeared later, but all conformed to a rather standard container based on 20 and 40 foot containers placed on Lgis 598 or Sgs 693 car types.
Variations in length and lettering have been offered thus far by Marklin, but another company worth a look at is FR (Freudenreich) whose line includes numerous interesting container freight cars lettered for international shipping companies interchangeable with the two Marklin car types. Marklin compatible couplers are also standard on FR freight cars.
More solidly constructed than Marklin, FR in partnership with MCZ Models produce containers which are finished along all seams and use the same pin specs as Marklin (NEM380 specification) thus fully compatible with designated container cars offered by both companies.
With two exceptions all FR containers are interchangeable with Marklin: FR #46.818.40 (4 car set sold out) and #46.818.14 (4 car set currently available) feature permanently cemented containers.
Not all containers are shipped by sea some are transported only by truck and rail owing to unique possibilities for model railroaders.
Note: FR and MCZ Models containers available at ZScale Monster Trains: http://www.zscalemonster.com/mcz/ and FR trains available directly from FR Freudenreich: https://fr-model.eshop.t-online.de/