Freight is shipped based upon it's market value, and shipping cost, not tonnage. Computers are hardly ever shipped by boxcar?

Tonnage is one factor of the cost of shipping, as are handling costs, security needs, etc.. But value of the goods being shipped and shipping cost are the reasons for the choice of various modes. Coal is low value, and when shipped in bulk on ships or trains is the least costly means of transport to utilities and steel furnaces. Container trains over long distances are competitive for higher value goods. Trucks beat trains for short to middle distances because of less time, handling, and capital costs.

Computers are expensive and are shipped by everything from container ships to air freight, depending on the need for the item. Flowers, fish, and fresh produce are even shipped by air freight daily. The ultimate example of value versus cost is package delivery to your door. The price you pay depends on when you want it.

The expansion of the Panama Canal will change the costs of handling containers and shipping them to east coast markets. Ships are generally the cheapest mode, but slower, railroads have more handling costs (known as break buld and consolidation costs), the more you handle an item the more costs in both time and handling it imposes. But, going to east coast ports via the Canal, and with the increased Canal fees, is longer and costlier, so any diversion would only likely reduce the rate of growth in already overtaxed facilities like POLA-LB.

And as to Russell's latest fantasy, when was this second Panama Canal started in the 70's? I was actually here is the 70's and don't have Alzheimers yet, and it's the first I've heard of this fantasy.

There has been planning to expand the canal since battleships and carriers got too big for the Panama Canal in the 1920's, even an article on using nuclear explosives to dig a new canal in Life magazine in the 1960's that I remember. But, to my knowledge, there was no secret conspiracy not to build a new canal, and none started "in the 70"s". Even this current venture has some serious economic issues, but is probably finally worth doing do to expanded world trade, especially between the west coast of South America and Europe.