Since the Large Hadron Collider (LHC) needs to be in tip-top shape to discover new particles, it has two inspectors making sure everything's in working order. The two of them are called TIM, short not for Timothy, but for Train Inspection Monorail. These mini autonomous monorails that keep an eye on the world's largest particle collider follow a pre-defined route and get around using tracks suspended from the ceiling. According to CERN's post introducing the machines, the tracks are remnants from the time the tunnel housed the Large Electron Positron instead of the LHC. The LEP's monorail was bigger, but not quite as high-tech: it was mainly used to transport materials and workers.