Using containers caused a huge reduction in port handling, thus lowering costs and helping lower freight charges and, in turn, boosting trade flows. Almost every manufactured product humans consume spends some time in a container. Containers are one of the important innovations of 20th century logistics.
By the 1920s, railroads on several continents were carrying containers that could be transferred to trucks or ships, but these containers were invariably small by today's standards.
The first vessels purpose-built to carry containers began operation in Denmark in 1951. Ships began carrying containers between Seattle and Alaska in 1951. The world’s first truly intermodal container system used purpose-built container ship the Clifford J. Rodgers built in Montreal in 1955 and owned by the White Pass and Yukon Route. During its first trip it carried 600 containers between North Vancouver, British Columbia and Skagway, Alaska on26 November 1955; in Skagway, the containers were unloaded to purpose-built railroad cars for transport north to the Yukon, in the first intermodal service using trucks, ships and railroad cars. Southbound containers were loaded by shippers in the Yukon, moved by rail, ship and truck, to their consignees, without opening. This first intermodal system operated from November 1955 for many years.
Containerisation revolutionised cargo shipping. Today, approximately 90% of non-bulk cargo worldwide moves by containers stacked on transport ship, with many containers originating from China. As of 2005, some 18 million total containers make over 200 million trips per year. Some ships can carry over 14,500 TEU (Emma Mærsk, 396 m long, launched August 2006). It has even been predicted that, at some point, container ships will be constrained in size only by the depth of the Straits of Malacca—one of the world's busiest shipping lanes—linking the Indian Ocean to the Pacific Ocean. This so-called Malaccamax size constrains a ship to dimensions of 470 m long and 60 m wide (1542 feet * 197 feet).
The widespread use of ISO standard containers has driven modifications in other freight-moving standards, gradually forcing removable truck bodies or swap bodies to adopt standard sizes and shapes (though without the strength needed to be stacked), and completely changing the worldwide use of freight pallets so that they fit into ISO containers or commercial vehicles.
Better cargo security is also an important benefit of containerisation: because the cargo is not visible to the casual viewer it is less likely to be stolen. The doors of containers are generally sealed so that tampering is more evident, which has reduced the "falling off the truck" syndrome that was a problem in the shipping industry for a long time.
Using the same basic sizes of containers across the globe has reduced problems caused by incompatible rail gauge sizes in different countries. The majority of the rail networks in the world operate on a 1,435 mm (4 ft 8½ in) gauge track known as standard gauge but many countries like Russia, Finland and Spain use broader gauges while many countries in Africa and South America use narrower gauges on their networks. Using container trains makes trans-shipment between different gauge trains easier when using automatic or semi-automatic equipment.
To read more about modern shipping and its development and history go to http://en.wikipedia.org