30-2224-1 SD-90 MAC Diesel Engine With Proto-Sound 2.0 For availability see 'Find it locally' tab $249.95Product InformationDescriptionSD-90 MAC Diesel Engine With Proto-Sound 2.0 - UP Cab No. 8039 Roadname: Union PacificProduct Item Number: 30-2224-1Catalog: BA 2001 Volume 2Product Line: RailKingDelivery Status: Delivered AUG. 2001 OverviewThe first experiments with AC (alternating current) rather than DC (direct current) diesel-electric engines began in the 1960s. They did not get going in earnest, however, until General Motors plunged into the field with its 4,000-hp SD60MAC in 1991-92, discovering that the AC motors increased an engine's adhesion and allowed it to start a far heavier train than a DC locomotive of the same horsepower. They discovered, however, that horsepower did matter when the engines tried to run at speed; the heavier load slowed the engines down and prevented them from reaching track speed. Things have moved quickly since these discoveries. By 1996 GM had delivered the SD-90MAC, an engine that was delivered with a 4,300-hp prime mover that was designed to be replaced by a 6,000 version as soon as it became available. Now that they are operating at full power with a GM16V265H engine, GM claims that one SD-90MAC can replace two SD40-2's in both heavy haul and high speed freight operations. M.T.H. is proud to present a replica of this massive engine in the markings of the Canadian Pacific, Norfolk Southern, and Union Pacific railroads. With Loco-Sound or Proto-Sound 2.0, which offers the most realistic operation in model railroading, your SD-90MAC will be the king of your layout. Pull-out fact: The SD-90MAC generates an astonishing 170,000 pounds of continuous and 200,000 pounds of starting tractive effort as well as 115,000 pounds of dynamic braking effort. Features - Intricately Detailed ABS Body - Metal Wheels and Axles - (2) Remotely Controlled Proto-Couplersr - Die-Cast Truck Sides, Pilots and Fuel Tank - Colorful Paint Scheme - Metal Chassis - Metal Handrails and Decorative Horn - (2) Precision Flywheel Equipped Motors - Locomotive Speed Control - All Metal Wheels and Gears Unit Measures:14 1/2" x 2 1/2" x 3 1/2" Operates On O-31 Curves Find It LocallyThis product may not have shipped yet or is completely sold out. Click on the show button to see who might have it on order. SupportSupport Content: