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Caterpillar was moving aggressively into the earth-moving specialty, since that was where the money was to be made. In 1941, it introduced a rubber-tired tractor, the DW10, designed to pull scrapers and other similar implements. The advantage of this tractor over the "crawler" type, was its speed in moving earth. Because of wartime demands, production of the DW10 was suspended in 1943, and would not be manufactured again until 1945. The DW10 pulled one of several implements: the LaPlant-Choate CW-10 Carrymor, the LeTourneau Model LS Carryall scraper, the Athey PD 10 side-dumping trailer, and the Caterpillar W10 bottom-dumping Wagon. The DW10 was built into 1954 when the DW15 was released as its replacement.
The DW10 was intended by Caterpillar to be a direct competitor with LeTourneau's rubber-tired scraper, the "Tournapull", which had been introduced to the market in 1938. Caterpillar viewed LeTourneau's "Tournapull" as a threat to the dominance of Caterpillar's "crawler" tractor in the earth-moving market. Although the two companies worked closely together during the major portion of the War, when their marketing agreement expired in 1944, it was not renewed. This released Caterpillar to manufacture earth-moving equipment that would compete directly with LeTourneau across its product line. And compete Caterpillar did!
In 1945, Caterpillar introduced its first bulldozer straight blades operated by cable control units. Its angle blades were introduced in the following year. They next offered hydraulic controlled blades in 1947.
In 1946, Caterpillar introduced its first pull-scrapers. These were designed to be used with the Caterpillar D6, D7, and D8 tractors, and the scrapers were designated the No. 60, No. 70, and No. 80, and all were operated by cable control units (essentially a winch on the rear of the tractor that controlled cables that controlled the adjustments on the scraper). These were followed by the No. 40 (to be used with a D4 and controlled by hydraulics) in 1949, and a No. 90 first produced in 1951 (cable controlled, to be used with a D8 tractor). Over the next several years, the designs for all of these pull-scrapers were modified with improvements. In 1955, the No. 80 was replaced by the No. 463; in 1956, the No. 70 was replaced with the No. 435; also in 1956, the No. 90 was replaced with the No. 491.
In 1950, Caterpillar began producing its new self-propelled rubber-tired scrapers - the two-axle, four-wheel DW20 and the single axle, two-wheel DW21 - intended to slice into LeTourneau's "Tournapull" market. Again, over the next few years, there were many design changes and improvements to these two models, but in early 1961, both models were discontinued. They were replaced by the 600 series Caterpillar introduced in 1962, with 7 new models. The two-axle models were the 641, 651, and the twin-engine 657. The twin-engine 657 was based upon a similar product manufactured by Euclid that it had introduced in 1949. The three-axle models were the 632, 650, 660, and the 666.