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War & Revolution. It took World War II to show road builders what their machines could do, set. off the technological revolution that produced today's giants. Bulldozers cleared the beaches, hauled artillery, built airstrips almost overnight, raised their blades as shields against bullets, and stormed Japanese positions. Admiral William ("Bull") Halsey ticked off the bulldozer as one of the four machines that won the war in the Pacific (the others: the submarine, the airplane, radar). Since then, manufacturers have steadily added power for greater speed and heavier loads; the average horsepower of today's tractor is 230 v. 130 in 1948—and still rising. Pneumatic tires, long confined almost entirely to LeTourneau equipment, became standard on most machines. Despite the size of today's juggernauts, power steering and other gadgets make a 30-ton machine almost as easy to maneuver as a cart in a supermarket.
Army on the Move. Though road building seems a jumble of confusion to the passing motorist, each machine has its own job to do in the mechanical army on the march. Foremen in jeeps hustle back and forth along the road, keeping in constant touch with field headquarters by two-way radio, instantly summoning machines for new jobs, mechanics for repairs. Growling bulldozers and rubber-wheeled scrapers with pelicanlike scoops clear and level the land. Compacters with huge rubber wheels or dozens of small steel feet pack down the loose dirt of the roadbed. Power shovels and 100-ft.-tall cranes with draglines are brought in to cut and eat through steep hills, swing out huge boulders, lift girders in place for bridges. Agile graders pare the shoulders and side slopes while ditchers with endless chains of buckets scoop out trenches for drainpipes. Then come the stone-crushing plants that can turn boulders into egg-sized aggregate for the road's foundation. After them come the pavers. For a concrete road, the paver moves along one side of the road, shooting out buckets of concrete on overhead rails; for asphalt, the paver straddles the roadbed, moving along as fast as 102 ft. a minute. Finally, the finishing machines smooth the completed road, and concrete saws neatly cut the joints needed for expansion and contraction.
Tough Competition. Chief among the firms whose technology and invention shaped and formed the art of road building is Caterpillar Tractor Co. of Peoria, EL, the industry's undisputed leader (1956 sales: $686 million, up 200% from 1947-49). Caterpillar early took the lead in the industry—and never lost it. It spent $1,000,000 in research to develop the first diesel tractor during the Depression, has since designed increasingly heavy, speedy and versatile crawlers. (Its newest model, the Dg, is a 320-h.p., 30-ton giant powerful enough to push or pull a 6.4-mile line of automobiles.) Today Cat manufactures 153 different machines for every use from agriculture to dam building, and there is scarcely a major road project in the U.S. where the telltale yellow of its powerful crawlers, big-bellied scrapers and grasshopper graders is not in sight. To keep Cat out front, President H. S. Eberhard is planning a $200 million plant expansion for the next three years, hopes to boost production 45% and to gross $1 billion by 1959.