flatcar
A railway freight car with a flat, open deck and no sides or roof, used for carrying containers, vehicles, or heavy loads.
The trucks shipped from the factory were transported on flatcars.
At this station, you can see the work of loading containers onto flatcars.
General term for a freight car; 平台型貨車 specifies the flat-deck type.
A container car, often a flatcar designed specifically for containers, but 平台型貨車 is a broader category.
Compound of 平台 (flat platform) + 型 (type) + 貨車 (freight car). The exact historical derivation is uncertain, but the term transparently describes a flat-deck freight car.