One of the greatest episodes of The Simpsons is, without a doubt, "Marge Vs. The Monorail." The Conan O'Brien-penned episode has everything you could ever want.

When it comes to wild-ass ’50s dreams about mankind’s imminent future in space, it’s tough to beat Freeman Dyson’s nuke-powered Project Orion, but this concept drawing of a rocket monorail is not half bad either. A rocket monorail!

Monorails used to be the vision of futuristic travel. Now, that mode of transit has been mostly reduced to inter-terminal airport travel and family theme parks. Take a step back in time and gander at these bullet-shaped babies in action.