As seen recently in a Boston Globe article, CISBOT is a cast iron joint sealing robot. Using CISBOT saves the gas company a lot of time and money. In one day, with one hole, the robot can seal 6 joints. Typically a human crew would need to dig one hole for every joint and it would take them about 3 days to fix one joint.
CISBOT is made by ULC Robotics and they make inspection and repair robots as well.
CISBOT works on a tether, sends back images and is controlled from above. Once the robot finds a seal that needs repairing, it drills a small hole and fills the area with sealant. CISBOT uses an anaerobic sealant that will last up to 50 years, saving the gas companies money.
Check out the video below of the robot in NYC.