At the 4,500-acre Transportation Research Center (TRC) proving grounds in East Liberty, OH, Cummins put its new 2017-compliant X15 and X12 engines through their paces, with trucks equipped with both the new engines as well as older Cummins models made available for "riding and driving" in a variety of scenarios; everything from engine braking deceleration tests on a one-mile straightaway to acceleration-cruising speed-deceleration runs on the facility's 7.5 mile oval track and low-speed maneuvering through a slalom course set up on a skid pad. (All photos by Sean Kilcarr/Fleet Owner)
