The Di 8 is a diesel-electric locomotive with a Bo'Bo' wheel arrangement. They have a weight of and are built for standard gauge. The locomotives are long, wide and tall. The wheelbase on the bogies is , while the wheelbase between the bogies is . The wheels have a diameter of when new. Each locomotive is equipped with a Caterpillar 3516 DI-TA prime mover and a fuel capacity of . This provides a power output of at 1,800 revolutions per minute, allowing for a maximum operating speed of . They have a starting tractive effort of 270 kilenewtons.