Some train tracks carry an electric charge to locate trains or detect blockages. This electricity can also charge a phone, as demonstrated by Ukrainian DIYers Pavel Pavlov and Aleksandr Kryukov.
Tracks carry a little less than 3 volts of alternating current. To harness it, lay a piece of metal across each rail and connect it to components that will convert the flow into direct current, stabilize it, and step it up to the 5 volts your phone needs.
So why not try this? Well, it would take a really long time to charge anything. Oh, and hanging around an active train line could get you arrested or killed. Most important, a bad circuit could fry your precious phone.
Editor’s note: Popular Science does not condone wanton charging of phones for purposes of internet virality.
This article was originally published in the January/February 2017 issue of Popular Science.