Recreating the 4-8-8-4 Big Boy Locomotive

By Blake Eskin

Paul Fischer makes 3D sketches of big, complicated machines for fun. He recreated the King Tiger and other German tanks from World War II, but that only made him more ambitious. “I was looking for something bigger to draw after tanks,” says Fischer, who has been drafting since high school.

So he ordered the original blueprints of the 4-8-8-4 Big Boy, an American steam locomotive used by Union Pacific Railroad from 1941 into the 1960s, when diesel supplanted steam. He began with the main drive wheels, which were in two parts. “Even something as simple as those wheels, I always assumed that they were one piece of metal.”

Fischer reconstructed an entire Big Boy engine, first in SolidWorks 3D modeling software and then in real life, on a MakerBot Replicator 2 Desktop 3D Printer in his basement in Earleville, MD. “From what it looks like on the outside, I made it as close to the original as possible,” says Fischer. Fischer spent between 700 and 800 hours drafting and another 1,000 hours 3D printing the locomotive.

All told, Fischer spent eight months on the Big Boy. At times, it was like having a newborn. “In the middle of the night I would hear the printer stop, and I would get up and start a new build.” Fischer went through 16 rolls of MakerBot True Black PLA Filament and two 2-oz. tubes of Zap Super Glue. “I used more Super Glue than I probably should’ve,” says Fischer. He filed some parts to fit them together, but the Big Boy is black, so there was no need to paint it.

The finished engine is six feet long. “Just short enough to fit in the SUV when I put the seats on one side down,” says Fischer, who drove his model up MakerBot headquarters in Brooklyn, NY. “It was a tough journey,” says Fischer, “But when I got to the end and saw the look on Bre’s face, it made it all worth it.”

As formidable a project as Fischer undertook, Union Pacific is restoring Big Boy No. 4014, which is now on display in Pomona, CA. At 132 feet long including a tender, it will not fit in an SUV, but Union Pacific will find a way to bring it to its Cheyenne, WY, headquarters, this spring.

If you’re an experienced model maker and want to make your own Big Boy, Fischer has posted a complete set of files on Thingiverse. You should finish your Big Boy before Union Pacific restores No. 4014. Or if you’re not ready to commit, you can start with the main drive wheels, like Paul Fischer did.