Three diesels on the Oahu. The two war-time GE 45-ton locomotives and then a 4- wheel plymouth that came later. The plymouth is now at the LK&P excursion line on Maui.
From looking at the photos on the Hawaii Ry Society website, and other photos that have been published the locomotives there are not like the GEs. The GE locomotives have articulated trucks with a body resting on top of the trucks. The engines at Ewa today are regular trucked locomotives.
GE made a number of these 45-ton narrow gauge articulated truck locomotives. The US Army bought some during WWII for possible operation on the 42" gauge lines. I guess they were thinking of either the Phillipines or Japan. I think a few went to Newfoundland.
After the war GE built a number of 3' gauge articulated truck locomotives for industrial service -- many for the steel industry. Huckleberry has one of these.
Brian Norden