"Campania" and "Lucania" had the largest triple expansion engines ever fitted to a Cunard ship, also the largest in the world at the time, and rank amongst the largest of the type ever constructed. The engines were 47 feet in height, reaching from the double-bottom floor of the engine room almost to the top of the superstructure - over five decks. Each engine had five cylinders: two high pressure cylinders, each measuring in diameter; one intermediate pressure cylinder measuring in diameter; and two low pressure cylinders, each measuring in diameter. They operated with a stroke of . Steam was raised from twelve double-end Scotch boilers, each measuring in diameter and having eight furnaces. There was also one single-ended boiler for auxiliary machinery and one smaller donkey boiler. Boiler pressure was , enabling the engines to produce , which translated to an average speed of , and a record speed of 23½ knots. Normal operating speed for the engines was about 79 rpm.