A complete machine shop on wheels cost the Government about $8,500. The carpenter shop cost $7,600. As supply units for the portable shops, the Government built 30 material trucks, each containing about 600 items of tools and supplies. These material trucks cost $6,100 apiece.
Another successful development of this nature was the portable photolithographic press truck, already referred to in the account of the American Expeditionary Forces' lithographic equipment. These automobile presses, which were at our front soon after our troops went into the trenches, were able to print and distribute lithographic sketches and maps within 12 hours after the original sketches were submitted for reproduction. The French and British armies also had mobile photolithographic units which were much less portable than ours and much slower in operation. The best time made by the French and British outfits was four days for the same work.
We also supplied to the Engineering forces abroad special water sterilizers and water tanks, mounted on trucks. The Engineers put small job-printing shops on trucks and photographic dark rooms on trucks for use in the field.
They equipped trucks with derricks, capstans, and wrecking machinery. They furnished automotive road sprinklers and oilers, as well as trucks with special dump bodies for highway work.
They developed a light, portable pile driver unlike anything used theretofore in commercial work. This machine was constructed of structural steel and had a total weight of 4 tons. It was mounted on a truck drawn by horses or mules, and the pile driver itself was operated by a 25-horsepower gasoline engine. The pile driver could be used within 16 minutes after its arrival at any point.
One development of this sort, the mobile clam-shell derrick, is worth noting. This unique piece of machinery was built by the Winther Motor Truck Co., of Kenosha, Wis. When the American Expeditionary Forces issued a requisition for 120 clam-shell derricks mounted on motor trucks, no such piece of equipment was in existence anywhere on earth. The Winther Co. volunteered to attempt to produce the machine. By giving a wider tread of rear axle to the Winther motor truck, the company could provide a suitable vehicle, but, search as they might, they could not find a derrick of sufficient power to operate a half-yard clam shell and also light enough to mount on a 7-ton truck. No such derrick existed. The company, therefore, without knowing anything about the manufacture of derricks, put its engineering force to work to produce a design. This design was developed in two weeks, and the derrick built from it was less than half the weight of any derrick of equal capacity. After being perfected, the mobile derrick in tests showed that it could move 350 cubic yards of sand or gravel per day or 500 or 600 tons of coal. One man could operate it and the motive power was a 4-cylinder gasoline engine.
ENGINEERS' TOOL WAGON.
