Tested starting in September 1963 and introduced the following July, the Tandem TS-14 motor scraper was part of the Euclid and Terex product line through at least 1968.
It consisted of a 7UOT single-axle prime mover and two scrapers, with the second yoked to the rear of the first. Each of the three axles was powered by a Detroit 4-71 engine rated at 134 flywheel horsepower. Just shy of 66 feet long, it weighed 93,600 pounds, and payload was 28 yards struck, 40 heaped, and 94,000 pounds. The front bowl was loaded first, then the rear.
Western Contracting, which had been a major Euclid customer, had a fleet of the Tandem TS-14s, and in the mid-1960s used them on one of its California Aqueduct contracts. Euclid conducted an ill-fated experiment in which two of these machines were yoked together with an A-frame coupler. This green snake on wheels was approximately 135 feet long with six axles, all powered to the tune of 804 total horsepower, and five pivot points—two for each Tandem TS-14 plus the fifth pivot at the A-frame. It was controlled from the lead prime mover, so the operator had restricted vision to the back of his machine. Capacity across the four bowls was 58 yards struck and 80 heaped, and the loading process was opposite that of a Tandem TS-14, No. 4 (back) bowl to No. 1 (forward).
The purpose of the three-week experiment was to see how safely it could be operated. Not very, it turned out. With all the pivot points, power at each axle, and no vision to the back, there was an estimated 10 to 15 feet of play at the rear scraper, particularly when the first one or two bowls were empty. The effect was a writhing motion, like pushing on the end of a rope. Not too critical an issue on a wide, flat area free of hazards, but things were different when it tried to unload on a narrow canal berm.
With all that side-to-side tracking at the back because the No. 1 bowl had been unloaded first, the No. 4 scraper’s left wheel caught the edge of the berm and the bowl started to slide over. The operator stopped the rig and bailed, refusing to go further in a dangerous situation. No cranes were available to retrieve the errant bowl, and efforts to power the serpentine machine forward and away from the brink were too late. Most of the train slowly slid towards or capsized into the adjacent excavation.
No major harm was done, but that was the end of the experiment, and Western continued to use Tandem TS-14s for several years afterward.
The Historical Construction Equipment Association (HCEA) is a 501(c)3 non-profit organization dedicated to preserving the history of the construction, dredging and surface mining equipment industries. With over 3,800 members in 25 countries, our activities include publication of a quarterly educational magazine, Equipment Echoes, from which this article is adapted; operation of National Construction Equipment Museum and archives in Bowling Green, Ohio; and hosting an annual working exhibition of restored construction equipment. Our next International Convention and Old Equipment Exhibition will be August 27-29, 2021, near Concordia, Kansas. Individual annual memberships are $35 within the U.S. We seek to develop relationships in the equipment manufacturing industry, and we offer a college scholarship for engineering and construction management students. Information is available at www.hcea.net, or by calling 419.352.5616 or emailing [email protected]