This is a command /setblock: /setblock 0 -60 48 rail. It’s basically this: /setblock is the command. 0 -60 48 is The Coordinates. And The rail is the basically the block it’s turning to. The Coordinates are where it is. So that’s it. Easy!
Here’s a few Examples… /setblock 1000 0 1000 Tnt or /setblock 1000 0 1000 Air.
