Elon Musk has unveiled his latest ambition to change transport in the 21st century, with a rail line that would connect Madrid and Barcelona in just 30 minutes. The Hyperloop project is just one of a number of innovative transport ideas that are still in the planning stages but beginning to seem less and less like science fiction. Here are a few examples, in no particular order, of transport ideas that could change our world:

1. Hyperloop. This is a transport system using reduced-pressure tubes in which pressurized capsules sit on an air cushion and are propelled by linear induction motors and air compressors. It’s one of the more realistic projects, and a test track has already been announced.

2. The Circle Line Travelator. Architects at NBBJ captured the world’s imagination earlier this month when news broke of their idea to replace London’s Circle Line with a three-lane walkway known as a “travelator”.

3. 3D Express Coach. A transport system that would travel above the traffic, this project was set for trial in Beijing as early as 2010, but never got off the ground due to fears about the maturity of the technology. The project remains under consideration in China and Brazil.

4. Planes of the future. Since the retirement of the Concorde, the holy grail of air travel has been to find a way to cover huge distances in a short amount of time. Numerous projects remain on the books, though none is planned for production in the foreseeable future. While some look to speed, others have looked to follow in the footsteps of the Airbus (following the success of the A380), opting for larger, lighter and more efficient aircraft.

5. Maglev trains. Short for “magnetic levitation”, these trains continue to beat world records, with Japan currently leading the charge with a high speed of just over 600km/h. While not yet in service at such speeds, the potential to connect distant cities is becoming a possibility.

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Author: Donald Armbrecht is a freelance writer and social media producer.

Image: A worker stands among CRH (China Railway High-speed) Harmony bullet trains at a high-speed train maintenance base in Wuhan, Hubei province. REUTERS/Stringer