|This article is about an older version of DF.|
In Fortress mode, you start with one or more immobile wagons that represent the transportation vehicles for all your supplies. A wagon is not a real vehicle, and never moves or serves any other purpose - it simply sits there at the start of the game, representing where your dwarves decided to stop. Any and all supplies were selected at embark by you and bought with points; supplies cannot be bought later, but your dwarves can (try to) trade for whatever the seasonal caravans bring.
To empty a wagon, your dwarves need the appropriate hauling labor enabled (all are enabled by default at embark), no other jobs to distract them, an appropriate stockpile designated, and a valid path between the stockpile and the items. And, depending on how many items you brought, patience.
You can can break down your wagon into three logs by pressing , highlighting the wagon, and pressing . A dwarf with the Carpentry labor enabled will then deconstruct the wagon into its component logs. The items will then be scattered in a slightly wider pattern in that same location. A wagon cannot be used for any other purpose - might as well break it down for the lumber, now or later.
If that dis-assembly is finished while a dwarf is returning to the wagon to haul an item to a stockpile, the dwarf will cancel that job. An announcement will be generated, to the effect of "Job Item lost or misplaced". Don't panic - nothing has been lost, except that dwarf's train of thought, as the item they were retrieving is no longer in the wagon but instead on the ground. They may adopt another hauling job, that same or a different one, and sooner or later that item will get hauled, but that particular job is cancelled for that moment.
If you bring a large enough quantity of goods with you during embark (especially during a reclaim), you can end up with multiple wagons.