A、It runs on a monorail. B、It can move on a monorail suspended from the roof of the tunnel. C、It is in position in the middle of

A design for a remotely-controlled fire engine could make long road or rail tunnels safer. It is the brainchild of an Italian fire safety engineer, who claims that his invention — dubbed Robogat — could have cut the death toll in the disastrous Mont Blanc tunnel fire in March 1999, which killed 41 people. Most of the people died within 15 minutes of smoke first being detected. Quick action is needed when fire breaks out in a tunnel. Robogat can travel at about 50 kilometers per hour. The Mont Blanc fire was five kilometers from the French end of the tunnel, so a machine could have got there in about 6 minutes.
The robot bas been designed and patented by Domenico Piatti of the Naples fire department. It runs on a monorail suspended from the roof of the tunnel. When the Robogat reaches a fire, it plugs into a water pipe running along the tunnel, and directs its hoses at the base of the fire. It is capable of pumping 3,000 liters of high-pressure water per minute—about the same rate as that from an airport fire tender. Normal fire engines deliver 500 liters per minute.
Question ：What is the main function of Robogat?

Why can the Robogat quickly get through to the scene of a fife?