Two kids who look to be in their mid teens sit in chairs with large remote controls driving these cars (that look like something from that Speed Racer movie) back and forth from the field of play where the hammer throw competition is happening. Usually after an athlete throws the hammer someone is there to take it from the official back to the start for the next athlete to throw. Not here, not at these Olympics. Instead the official takes the heavy hammer and places it into the car, which is then driven back to where the kids are sitting. They have two of them so as one is coming back to the start the other is on they way to the end. I'm told the cars are also used to transport the discus and javelin as well.