the same operational flexibility as smaller units, limiting its possible customer base to only the largest railroads. Also, since the H-engine was a new design it hadn't reached the same level of reliability as EMD's previous engine. The low reliability on such a large engine was an especially bad combination since the loss of one engine in a train meant the loss of a larger percentage of pulling power than had a smaller engine failed. In the end the SD90MAC-H was only delivered to two railroads, the Union Pacific Railroad and the Canadian Pacific Railway. The Canadian Pacific locomotives were part of an earlier order for 710-engine equipped SD90MAC locomotives that was still in production when Electro-Motive Diesel switched over to the H-engine. Electro-Motive Diesel also tried offering a lower-power version of the SD90MAC with a 12-cylinder engine called the SD89MAC, but none were produced other than the prototype. Specifications Prime mover (EMD 710): EMD V16 710G3C-T1 Power Output - Idle - 200 rpm Full Speed - 950 rpm Prime mover (EMD 265): EMD V16 EMD GM16V265 Power Output - at 1,000 rpm Idle - 200 rpm Full speed - 1,000 rpm Traction motors: 6 Siemens 1TB2830 AC motors mounted 3 each on 2 HTCR-2 radial self-steering trucks. Rated output - Gearing - 83:16 Wheel size - Max revolutions - 3,435 rpm Starting torque - Continuous torque - Maximum voltage - 2,183 V Performance (parenthesis indicate H-Engine equipped specifications): Maximum speed - Starting tractive effort - and ) Continuous tractive effort - and ) Braking effort - Weight - / Fleet rosters Canadian Pacific 9100-9160 (SD9043MAC): Units were at one time up for sale in "as is" condition, but no buyer was ever found. Some units had been intermittently placed into freight service to help combat motive power shortages. 30 of them will be rebuilt in 2019 as EMD SD70ACUs and renumbered 7000-7029. It was later announced that the order would be upped to 60 units in total, using the remainder of the 58 usable cores from the long-stored SD90MAC fleet and buying two SD90MACs from the Union Pacific to make up the difference. In 2021, Canadian Pacific purchased 40 more SD90MACs from Union Pacific for further continuation of the SD70ACU rebuild program. 9300-9303 (SD90MAC-H): These were scrapped in Lachine, QC. CEFX 100-139 (SD9043MAC) (Lease Fleet) 10 units traded to NS for 15 MP15DCs. EMLX 8500, 8523-8561 (EMD Lease fleet),