A contractor, inventor and manufacturer, George E. Logue Sr. spent his life collecting and maintaining antique tractors. On April 10, heavy-equipment enthusiasts will have the rare opportunity to buy Logue's hoard at an unreserved auction.

"Almost 100% of the auction is antique tractors, which is unusual for us," says Scott Edwards, territory manager for Ritchie Bros., which will hold the auction at Logue's farm in Trout Run, Pa.

The storehouse of nearly 100 pieces of vintage machinery also includes parts and other heavy equipment from construction's past. Among the most valuable items is a 1935 Caterpillar RD8, which is believed to be the third unit built in the series. Also up for sale is a 1933 Caterpillar 48 Elevating Grader, which was once used to build the Alaskan Highway.

"I've had calls from throughout the United States, Canada—all over," says Edwards. "This is definitely a once-in-a-lifetime thing."

Logue, who died this past October at 85 years old, fell in love with yellow iron as a child and spent the rest of his life collecting antique construction equipment. Ritchie Bros. estimates the value of Logue's collection at around $500,000; the machines might be worth more if they didn't cost so much to own and operate.

"They are expensive to transport, expensive to store and expensive to fix," says Bob Logue, son of the late collector. "Dad didn't do it because it was a good investment. He did it because he loved them."

A U.S. Army Air Corps veteran who earned a degree in agricultural engineering from Penn State in 1951, George Logue went on to live his dream of working with big machinery. Although Caterpillar was his favorite brand, he ended up working for a competitor.

"He applied for a job at International Harvester and Caterpillar," says Bob Logue. "Cat offered him an interview, and International offered him a job. He took the job."

Logue served as manager of field testing for International Harvester in Huntsville, Mo., but he moved back to his ancestral home in 1954 to open a construction business in Williamsport, Pa. Inside his machine shop, which started in the basement of his house and eventually grew to become a manufacturing business, Logue made a backhoe from scratch to use on his firm's construction projects.

"He was an amazing guy," says his son.