Today we have something special - the world's largest and most powerful single frame locomotive ever!
DDA40X History: Our story starts with Union Pacific who was, at one time, famous for BIG locomotives, the most famous of them being the Big Boys, but UP rostered several other enormous locomotive types, from various manufacturers, and of different types - steam, gas turbine, and diesel.
These various locos had varying levels of success, from great to dismal. Today's subject, the DDA40X, was thankfully a very successful class, being powerful, rugged, and dependable. 47 were built by EMD exclusively for UP from April 1969 and September 1971 (the frames were built by the John Mohr Company of Chicago, as they were too large for EMD's factory), and were commonly known as "Centennials" - this was due to the first units being built in 1969, which was the centennial anniversary of the first Transcontinental Railroad's Golden Spike ceremony, and a Centennial, built in April 1969, would pull UP's Golden Spike celebratory train to Salt Lake City on May 10, for the anniversary celebration. The DDA40X boasts 6,600 horsepower, which is produced by two EMD 645E3 turbocharged V16 prime movers. These prime movers powered eight axles, which provides part of the name, the "DD", which is the Association of American Railroads' term for a locomotive with 2, 4 axle trucks, with all axles powered -"X" stands for experimental. The locomotive is 98' 5" long, could hold 8,280 gal of fuel, and weighed a whopping 545,000 lbs. Often, they were paired with "Fast 40s", which were EMD SD40-2 locos with special high speed gearing, enabling freight trains with this loco combo to travel as fast as 90 mph. They would serve UP well, but eventually ideas on motive power changed, and instead of huge, single unit, extremely powerful locos, railroads, including UP, realized that using several smaller, "normal" locos, was better overall. Thus, the Centennials were phased out. Some were scrapped, but 13 survived, in various conditons - mostly in museums. UP 6936 was owned by UP and used as part of their Heritage Fleet until 2016, and in 2022 it was donated to Railroading Heritage of Midwest America, where the loco has recently been restored to operating condition.
UP 6918 History: Our star loco today was built by EMD in November of '69, and had a succesful, if uneventful, service life until May 16 of 1985, when it was retired. It was traded to EMD a year later in May 1986, who would sell it to St. Louis Auto Shredding, who would scrap it.
Here's a photo of it operating.
Note the air raid siren on the cab roof - an experiment by UP to warn maintenance-of-way crews of an approaching train. It was short lived.
These have the distinctive early EMD wide nose cab, but it's not the "Safety-Cab/Canadian Cab" - the DDA40X did not have the structural reinforcements the safety cab does.
Note the General Telephone & Electronics "KarTrak" label - the multicolored barcode plate on the handrails. This was an early attempt at logging train movement and consists. It was just what it looked like - a barcode. It would theoretically be scanned by a trackside scanner setup, exactly like a modern barcode. Or not. Grime, wear-and-tear, and weather all made the system completely unreliable. It failed, and the idea abandoned by 1977.
The trademark gap between the prime mover bodies.
And the issue...
A damaged step.
Good - Almost everything! The paint and lettering looks really nice, and the overall details were top notch. The DCC worked just right, and the sounds are spot-on. It operates perfectly, handling trackwork and trains flawlessly. Weight came up to 1 lb 10 oz - good and solid.
Bad - The damaged step, which I could mostly push back into place, so it's almost totally unnoticeable. That's it.
Verdict - It's great. Looks fantastic, and operates perfectly.