Freight trains have freight carriages to carry goods from one place to another. Some are boxcars (closed and roofed cars for cargo); others are special so they can carry special cargo. There are hopper cars for sand, coal, ore and other granulous (sand-like) materials, flatbed cars for vehicles and machinery, tank cars for liquids, container cars for containers and even bottle cars for molten iron. Almost anything which is not too large to fit under tunnels and bridges can be transported on special freight carriages.