triple-expansion steam engine. Exhaust steam from the low-pressure cylinder of each of these engines powered a Parsons low-pressure steam turbine that drove her middle screw. The combination of three screws, two piston engines and one low-pressure turbine had been pioneered in the New Zealand Shipping Company's refrigerated cargo liner , launched in 1908. The same company then ordered a passenger liner with a similar combination, , which was launched in 1910. The giant s and several other passenger liners had also been built with similar "combination machinery". It offered better fuel economy and speed than propulsion purely by piston engines, and more flexibility than pure turbine propulsion. Niagara had two double-ended and six single-ended boilers, heated by a total of 40 corrugated furnaces. The boilers supplied steam at 220 lbf/in2 to the high-pressure cylinders of her triple-expansion engines. She was equipped to burn either coal or oil. On her maiden voyage she burnt coal. Niagara was the first oil-burning steamship to be certificated by the Board of Trade to carry passengers. Oil was both a more efficient fuel and could be bunkered more quickly. In 1913 it could take a week to bunker a large liner with enough coal to get from Sydney to Vancouver, and she would need to be bunkered again in Vancouver to make the return voyage. Niagaras fuel tanks had capacity for 5,000 tons of oil, and she could bunker enough oil in 30 hours to make a round trip from Sydney to Vancouver and back. This was a valuable saving in both time and harbour dues. Accommodation Niagara was built with berths for 281 first class, 210 second class and 176 third class passengers. Her first class accommodation was amidships, spread over her main, upper, shelter and promenade decks and included two cabins de luxe, each with its own bathroom. Her second class accommodation was aft, and third class accommodation was in the forward part of the ship. Much of Niagaras interior décor was in historicist styles. One of her first class cabins de luxe was in Louis XIV style. Her other cabin de luxe and her first class music room were in Adam style. Her first class dining saloon, lounge and library, and second-class music and smoking rooms were all in Louis XVI style. Her second class dining saloon was in Georgian style. The ceilings of the first class dining saloon and smoking room