Growing up in Long Island, New York, 13-year-old Caroline Crouchley is all too familiar with the country's archaic train systems. "My dad and brother take the train to [Manhattan] every day, so its a big part of my life," Crouchley tells CNBC Make It. She hears firsthand every day about the overcrowded trains, delays and long commutes times. And with environmental concerns looming large, especially among her eighth-grade classmates, Crouchley set out to create a better solution to commuting. What she came up with was a new take on Elon Musk's proposed hyperloop, an ultra-high-speed transit system that would send self-propelled transportation pods through low-pressure vacuum tubes at speeds of about 700 miles per hour.

A conceptual rendering shows the Hyperloop passenger pod inside a low-pressure transit tube. Source: Elon Musk

Elon Musk's hyperloop is really expensive," Crouchley says. In 2013, when Musk announced the plan for Hyperloop, he estimated the cost of a building a route from Los Angeles to San Francisco this new underground tube project at around $6 billion to $7.5 billion (though some projects could cost significantly more) and it would take 20 years to build. Crouchley also believes their are safety risks involved with transporting people through vacuum tubes. (A spokesperson for Musk's The Boring Company did not immediately respond to CNBC Make It's request for comment on potential issues.) "So I wanted to see if there was a different design that we could do that still used renewable energy," she said. What Crouchley came up with "has a simpler design, can be more easily constructed, can utilize the existing footprint of rail right of ways, and is cheaper to build," Crouchley told Fast Company. Her idea won her second place in the 2019 3M Young Scientist Challenge. (The first place winner is 14-year-old Kara Fan, who invented a nano particle liquid bandage that could potentially replace antibiotics.) For her design, Crouchley says she utilized Musk's pneumatic tubes, but instead of having passengers travel inside the tubes via pods, her idea was to use the pods and tubes to propel existing trains.

Crouchley's design calls for tubes to be built next to train tracks. A shuttle that travels inside the tubes would attach (via a magnetic connector arm) to existing trains outside the tube. When the shuttles were propelled via renewable energy (like solar and wind power) through the tubes, they would move the train at speeds faster than trains currently go in the United States, but not as fast as Musk's hyperloop is projected to go. (The fastest train in the U.S. is Amtrak's Acela, which can reach speeds of 150 miles per hour in a few areas of track, but averages about 82 miles per hour.)

A rendering of Caroline Crouchley's pneumatic train Credit: The Crouchley Family