examples of freight cars [1]
The shape of the cars varies depending on the type of cargo being transported.
caboose 
Car that is usually at the end of the train; it houses personnel, provisions and tools.
refrigerator car 
Closed-box insulated car with a refrigeration unit for carrying perishable foodstuffs.
hopper car 
Car for carrying bulk cargo; it has dump doors on the bottom for unloading the cargo.
livestock car 
Car with slatted sides for carrying livestock; it sometimes has two decks.
box car 
Car covered with a waterproof casing and having sliding side doors, for transporting cargo that must be protected from the weather and theft.