One of the most intriguing chapters in Amtrak and EMD history belongs to EMD Demonstrator #268, a unique SDP40F that lived two distinct lives. Originally constructed as an Amtrak SDP40F passenger diesel during the railroad’s early years of equipment standardization, this unit later became the property of General Motors’ Electro-Motive Division (EMD) and served as a development testbed for advanced traction and propulsion technology.
The SDP40F itself was Amtrak’s first purpose-built six-axle, 3,000 HP passenger diesel locomotive, designed to haul long-distance trains across the national network with steam-heated equipment. While the class was ultimately replaced by the more versatile F40PH, the SDP40F era remains one of the most significant transitional periods in Amtrak’s diesel roster.
Demo #268 stands apart from the rest, after Amtrak returned or traded back many of its SDP40Fs during the mid-1970s and early 1980s in favor of newer locomotives, EMD retained this demonstrator unit for experimentation. In the late 1980s, it was modified with advanced electrical components and AC traction gear as EMD explored next-generation propulsion systems under internal development programs. This testbed history and rarity make #268 a fascinating prototype for both Amtrak and EMD enthusiasts.
Now, Sunset Models 3rd Rail proudly offers this unique Demo #268 SDP40F in O Scale with a level of accuracy and refinement that rivals brass, featuring an ABS plastic shell, die-cast chassis, and fine brass detail parts for true museum-quality presence.
Model Features
• Precision ABS Plastic Shell with Die-Cast Metal Chassis
• Fine Brass Detail Parts for Maximum Accuracy
• Powerful Can Motor Drive for smooth, quiet performance
• All-Wheel Drive and Electrical Pickup
• Advanced electronics: 3R ERR Cruise/TMCC/Railsounds compatible with TMCC/Legacy/DCS, 3R Conventional for your choice of sound, and 2R ESU Loksound 5.0. Blunami is available as well
• LED Lighting Suite — headlights, number boards, marker lights, and strobes as appropriate
• Minimum Curvature:
– O-54 curves (3-Rail)
– 48" minimum radius (2-Rail)
• ERR Cruise is compatible with Legacy, DCS, TMCC, and Conventional control systems, Blunami is not and indepently operated through the iPhone or Andriod Apps.
A Unique Chapter in SDP40F History, Now in O Scale
The EMD SDP40F played a pivotal role in Amtrak’s early diesel era, powering iconic long-distance trains across the United States. When its passenger career wound down, many SDP40Fs were returned to EMD and traded for F40PH power, but #268 remained behind the scenes, rebuilt and re-engineered as a test locomotive that helped shape future traction technology.
Sunset Models 3rd Rail honors this one-of-a-kind story with an O Scale representation that captures the look and spirit of the demonstrator unit, from its Amtrak beginnings to its EMD testbed legacy.
Reserve your Demo #268 SDP40F today and add a rare and historically rich prototype to your O Scale roster.
Photo courtesy of locomotivewiki.com https://locomotive.fandom.com/wiki/EMD_SDP40F/Gallery
and the dieselshop.us
