This train layout is so small it nearly defies photography as much as it defies expectations. Built by model railroad enthusiast [David Smith], this is a model of a model: an N scale (1:160) layout inside a Z scale (1:220) world! For size reference, the entire layout is shown under a ballpoint pen tip in the photo above. And it actually runs!
Of course with this being Hack a Day you know there’s going to be some shenanigans involved. Pause the hi-def YouTube video at the 0:50 mark and see if you can puzzle it out first. The remainder of the video and [David’s] project page reveal how this all works, and it’s no less amazing even with the trick exposed. Check out his other ludicrously small mechanical wonders as well!