by Alex Kunce

Ravensburger’s GraviTrax systems use the power of gravity to propel marbles around the tracks you build. Across chutes, ramps, curves, and inclines, the GraviTrax system is a great display of kinetic force and propulsion. I decided to challenge myself, using only the pieces of a single base kit and a few fun extension packs, to build a simple track. The only catch? I’d design it three times, each branching from a single center, all three exactly mirroring the other two.

Did it work? I’m happy to inform you that it turned out great. Starting at the center of an elevated tower, the three colored marbles begin outward from their starting block. Each curves around and into a chute to quickly reverse direction inward while also dropping a level. Here, the marbles’ paths turn outward again (decreasing momentum) and into longer tracks. Then they propel over the lever jumps; the force of the marble pushes the lever over, tipping it to jump back onto the track ahead. Finally, they careen into each other in the center of the track—two stories below where they’d started in the first place.

See how it works!

The limited resources meant I only had so much to work with while building. I had to find a way to decelerate the marbles, which flew off when hitting the turns too quickly. I used gradual turns to slow the marbles down while maintaining enough speed to keep them going on flat spots. Another challenge was spacing the lever jumps. Too short, and the arm would deposit the marble onto the ground, not back onto the track. Too far, and the marble would overshoot the track. I didn’t have many risers by the end of the design, so I was struggling. Finally, I hit a balance that worked. To conserve risers, I was slowly lowering the platforms to their minimum. When I tried to remove another layer of risers, the whole thing fell apart. It took a little while to put it all back together. The pieces are sturdy, but building with minimal risers meant the foundations of the tall structure were unstable. In the end, though, I got it all back as it was, and the track finally worked.

If I did this project again, one thing I might improve is resetting the track. Since the marbles end in the middle of the bottom tier, it’s difficult to fish them out by hand. Adding more risers would allow me better access to the lower tier. Otherwise, I am happy with how the project turned out.

I hope you enjoyed the project. GraviTrax is an excellent exercise for the mind, and I always enjoy finding new ways to use gravity and physics in tandem to make even more interesting courses.