NEW ORLEANS — THE Industrial Canal Lock in New Orleans connects two of America’s highest-tonnage waterways: the Mississippi River-which handles more than 6,000 ocean vessels, 150,000 barges and 500m tonnes of cargo each year, as well as much of its grain, corn and soyabean production-and the Gulf Intracoastal Waterway, which runs from refinery-rich south-eastern Texas to Florida. Ships pass from one to the other via a lock that was built in 1921, and is 600 usable feet long, or half the length of a modern lock. Its replacement was authorised in 1956. Construction on the replacement was authorised in 1998, and then stalled by lawsuits. The most optimistic predictions of the Army Corps of Engineers, which maintains America’s inland waterways, see the new lock being completed in 2030.

A few miles upriver from this archaism sits the Port of New Orleans, one of America’s busiest and most diverse. Like its rivals, the port is ‘intermodal