At the risk of massively oversimplifying how space travel works, here’s a dirty little secret: Actually traveling long distances in space isn’t that difficult or expensive. At least, not compared with the really hard and costly bit, which is to get a spacecraft traveling fast enough to cross such vast distances and then slowing it down again once the destination is reached. It’s not the speed but the acceleration and deceleration that gets you.

All that is the big idea behind the Solar Express, the brainchild of Montreal designer Charles Bombardier. His concept calls for massive space trains to crisscross the solar system at speeds up to one percent that of light, all without having to waste energy on pesky things like stopping. As he explains on the Solar Express website, the trains themselves would never stop moving once they got started. Instead, smaller craft would rendezvous with the moving Solar Express and transfer cargo and passengers.

In this vision of the future, a space traveler would use the “local” transport — say a space shuttle, or maybe even the fabled space elevator — to leave Earth for outer space and catch a passing Solar Express. At that point, the Moon could be reached in mere hours, Mars in a couple days, and even the outer planets like Jupiter and Saturn wouldn’t take more than a week or so to get to.

Of course, this all remains strictly science fiction for now: Bombardier himself acknowledges his concept still has tons of unanswered questions in terms of how such a complicated vehicle — or fleet of vehicles — would actually work, let alone how much it would cost. File this under flights of fancy for the foreseeable future, but as flights of fancy go, this is a particularly good one.