Photo courtesy of Ritchie Bros. Auctioneers This 1932 Caterpillar tractor, which sold for $55,950, helped usher in the diesel era. Related Links: Nearly 100 Antique Tractors To Cross Auction Block Obit: George E. Logue Sr. Bidders from around the world had the rare chance to pick through a large auction of vintage heavy equipment, including dozens of crawler tractors, graders and other machines, on April 10 in Trout Run, Pa."The turnout was huge," says Bob Logue, son of the late George E. Logue Sr., a contractor who spent much of his life piecing together the collection.Sales at the two-hour auction,
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.