Mack Trucks Historical Museum curator Don Schumaker told Cars.com in 2018 that his Mack ED could carry up to 7,000 pounds, but its 67 horsepower didn't allow for more than 50 miles per hour.

The HDTs play a role in construction and upkeep of infrastructure assets. The additional vehicles are part of the previously announced firm-fixed price $296 million contract over seven years that the ...