CERN’s Large Hadron Collider, the world’s premier particle detector, has a couple of new employees—both named TIM. The robotic inspectors can make their way around the detector’s almost 17 miles of tunnel autonomously, according to Engadget. The two TIMs—short for Train Inspection Monorail—will check the system’s oxygen levels, temperature, structure, and communication bandwidth, ensuring the world’s largest and most powerful particle detector is operating at its best.

The robotic inspectors move around the tunnel on a monorail suspended from the ceiling, and carry the instruments that provide feedback on the tunnel’s status in small wagons. Each device moves at a speed of slightly less than 4 miles per hour and uses infrared and visual imaging to allow scientists to monitor the tunnel. The inspectors can also pull other wagons with specific instruments as needed.

Right now, the TIMs are still located in a service tunnel awaiting their marching orders, but the duo should be chugging along pretty soon.

[h/t Engadget]