(Due to the number of emails we have gotten telling us about the restoration of the Union Pacific Big Boy locomotive that was stationed at the Fairplex in Pomona California, we’re re-running our love letter to these giants here today. This ran back in 2010 originally- Brian) We’re going huge by large with this Motorized Freak of the Week. While it may be slightly disrespectful to call a steam locomotive a freak, this machine qualifies on sheer size. Here is the Union Pacific “Big Boy.” There were 25 of these locomotives built between 1941 and 1943 and for all intents and purposes they are among the largest and most powerful steam engines ever produced, anywhere.

These engines were specifically designed by the Union Pacific Railroad to tackle a difficult run that required the use of helper engines to pull a fully loaded train over its never ending 1.15-percent uphill grade. Since it was costing the railroad too much money to assign multiple engines to this one route, the company had its engineers do the math to come up with a train that could do the job by itself. Because of the riggors of the route, the trains were capable of operating nearly anywhere else in the country. Simply put, they could handle anything.

What the engineers designed was essentially a steam engine on steroids. Size is all about perspective and to give you some of that, the fire box (where the coal is shoveled in and burned to heat the boiler to make the steam) on one of these things is large enough to fit 32 school kids inside of. That was proven by a California school teacher and train enthusiast a few decades ago.

We can only image the cackles of delight from the egg heads as they ran their slide rules around sketching out this massive beast.

The locomotive produces over 6,000 hp, it can pull a train weighing nearly eight million pound by itself up a grade of over 1.15 percent, it is capable of running at 80 mph (although they never ran anywhere near that in service), they have a piston bore of 23-¾ inches and a stroke of 32 inches and the drive wheels are 68 inches in diameter. The engine and coal tender itself weigh 1.2 million pounds. The train consumed 12,500 gallons of water per hour and in the same amount of time would burn 22,000 pounds of coal. This kids, is serious freaking business.

They were tasked with pulling all manner of stuff, but most of the time they were pulling refrigerated cars full of fruit and food. During the war effort these trains carried war material to the west coast and did it with speed and efficiency. They have been mentioned as unsung heroes and an important factor of the Allied victory. Apparently, during the war, Germany sent some spies to the country to observe our transportation systems, including the rail system. They reported on what they had seen with the regard to the Big Boys and the German government dismissed the report as pure fantasy. They clamed it was impossible to build such a thing.

These were among the last operating steam engines in the country with the last known work being done in 1962. Over their 20-year lifespan every one of the 25 engines racked over 800,000 miles, with the most used one heading north of 1,016,000 miles.

Here’s a little train knowledge. This is known as a 4-8-8-4 engine. What that means is that there is a truck of 4 non-driven wheels in the front, two sets of eight driven wheels in the middle, and a final set of 4 non-driven wheels at the rear. All those wheels are necessary to provide enough tractive force to allow the train to pull its massive load without, quite literally, spinning its wheels.

To think that these babies went from paper to tracks in just a couple years before the dawn of computers is awesome. There were no CNC machines, no CAD/CAM software, nothing. Just slide rules, graphing paper, and skilled craftsman.

Gives you chills doesn’t it?