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.
