Beer pipelines, sleepers and ballast: how things really move over land
Pipelines are a form of land transport, and not only for oil and gas. Short systems carry sewage, slurry, water and even beer, while pneumatic tubes shoot solid capsules along on compressed air. Anything chemically stable that flows can be piped, which makes the pipe the quietest vehicle on the ground.
Every land journey runs on muscle, animals or machines. People still walk, cycle and skate, and human power has even been used to fly. Working animals can be ridden, loaded as pack carriers, or harnessed alone or in teams to pull sleds and carts. Many historic roads were simply recognisable routes that nobody ever paved or maintained.
The car dominates roads, and by 2002 there were 590 million of them worldwide. Only road vehicles can deliver from door to door and switch lanes, routes and timing at will, which is why trucks usually handle the first and last legs of a freight journey. The trade-off is that cars carry few people for the space and energy they use and are the main source of urban noise and air pollution.
Railways lay two steel rails across sleepers of timber, concrete or steel that keep them a fixed distance apart, all bedded in gravel ballast. Steel wheels on steel rails roll with far less friction than rubber on asphalt, so trains beat road vehicles on energy use, though ships beat trains. Trains have been pulled by steam, diesel, electricity, horses, cables and even gravity. Specially built high-speed lines reach 350 km/h, and since the 1960s container trains have taken over most general freight from hand-loaded box cars.
Cable systems, from aerial tramways to escalators and ski lifts, drag vehicles up steep slopes with no motor aboard. Airports and seaports depend on ground links at each end; Denver and JFK work with livery firms to offer many options. Building these networks is often financed with debt and repaid through tolls or landing fees, and because planners tend to overestimate passenger numbers, projects frequently deliver smaller benefits than promised.
Source: Land transport
