When big is mentioned in model railroading this Union Pacific DD40A Centennial locomotive should be on the top of the diesel list. Back in 1969 I saw my first one at the Golden Spike celebration in Ogden, Utah. It was so new the paint was barely dry. They took 2 GP40 engines and put it in one long carbody with the thinking they just doubled the horsepower of a single loco. So what could be the downside to that thinking?
Lloyd was running this 32 car coal train today (Sunday) and as you can see the difference in length to a normal diesel. The downside to this thinking was when one engine failed they had 2 engines out of service. They lasted about 20 years before they were retired. There is still one in the UP Historical collection along with the operating UP 8444 Northern and the 3985 Challenger, a smaller version of the Big Boy.