I live near a train track that has a CN freight train go by. They seem to attach three locomotives to the front before the grain and petrol containers. I know that cargo ships have a maximum of human cargo they are allowed to have if one chooses to travel by sea, even though the ship's main function is cargo. I'm wondering if the freight trains are allowed to have the same—someone say going from the interior to the coast would prefer to take a train over a plane or car—or if they are strictly containers.