The Polar Express & Back To The Future Share A Universe - A Wild Theory Explained

Depending on who you ask, "The Polar Express" from 2004 is either a holiday classic or the ultimate example of the uncanny valley. But if you can get past the characters' dead eyes, you may notice some "Polar Express" details you missed the first time you watched it. For example, a fan theory posits that "The Polar Express" and "Back to the Future" exist in the same universe.

The theory has gained traction on TikTok thanks to @its_ivanmars, but it's been around for a while. Redditor u/Noggin_and_Loggin wrote about it years prior, but essentially, there's a point in "The Polar Express" where the flux capacitor from "Back to the Future" is seen inside of the train. There's another moment where viewers can see a newspaper clipping of Santas on strike, with one holding a sign that references the Lone Pine Mall. That's the name of the mall in "Back to the Future" after Marty (Michael J. Fox) changes the past, suggesting "The Polar Express" takes place in this new timeline. 

The Redditor even takes it a step further, suggesting the Conductor and Hobo, both voiced by Tom Hanks, are Doc Brown's (Christopher Lloyd) children. It would explain how they wound up with Doc's technology, but regardless of familial connections, it does seem to imply the two stories are part of the same world. Theoretically, the Polar Express could even be Doc's train at the end of "Back to the Future Part III." More than likely, however, these are just fun Easter eggs.

Who's to say "Back to the Future" and "The Polar Express" can't exist in the same universe? They both deal with fantastical concepts that play around with ideas surrounding time. However, the most likely explanation for these Easter eggs is that Robert Zemeckis directed both films. The flux capacitor and Lone Pine Mall references are probably nods to Zemeckis' earlier work, but incorporating time travel into "The Polar Express" may help explain a few things. 

After all, the train gets from North America to the North Pole and back pretty quickly. While one could describe this as magic, it's also possible there's advanced science at play where the train is able to travel through time and space to get everyone where they need to go. There's also a chance Doc Brown became friends with Santa at some point. When Santa takes off at the end of "The Polar Express," his sleigh emits fireworks in its wake. It's reminiscent of how the DeLorean would leave trails of fire when it traveled through time. Perhaps Doc gave Santa a time-traveling boost to allow him to go to millions of homes in one night. 

One final Easter egg: at one point, Hero Boy (Josh Hutcherson) pulls the train whistle and says, "I've wanted to do this my whole life!" In "Back to the Future Part III," Doc does and says pretty much the same thing. It doesn't really bolster the central argument of the fan theory, but it's clear the team behind "Polar Express" had fun paying homage to Zemeckis' filmography.