The light train is a maglev train that travels around the world at near the spead of light in a air-tight tube with the air sucked out of it. However, it is only supported above the ground by magnets, it is propelled by electromagnetic hoops at points along the track and pull it forward at progressively smaller intervals, like a enormous motor. The passengers on the train would stay on the train for two weeks and exit it 80 years in the future.
While the concept is intriguing and according to Stephen Hawking's calculations, plausible, there are some problems with the practical physics.
First off is centrifugal force. The earth is a gigantic sphere. A loop around it will create slight centrifugal force that becomes statistically significant as the train progresses towards the speed of light. The train will be ripped off the maglevs and forced against the top of the airtight tube. The passengers will also be crushed against the roof of the train.
There is also another problem. While two weeks is short for the passengers, it is quite a long time for a terrorist or genocidal murderer two bomb the track or sabotage any part of the mechanism. Like it or not, it will be a pain in the !@# to guard the track and prevent such shenanigans.
I just thought I'd share this concept with you guys.
TO THOSE WHO DO NOT UNDERSTAND THE PHYSICS OF THE TIME TRAVEL ITSELF
As any object nears the speed of light, they can't move faster because doing so would be moving faster than light, which is impossible because the object has to have mass. As they put more and more energy into moving faster, the energy has to go somewhere, so instead of moving through space, they move through the closest thing: time.