also what about safety? If there is an accident then you will have a huge pile of cars/sleds crashing into each other; How do you get injured out of a narrow tu

also what about safety? If there is an accident then you will have a huge pile of cars/sleds crashing into each other; How do you get injured out of a narrow tunnel? What about fires? What about ventilation (in case of fire) ? These are all problems of tunnels, now the narrow tunnel makes these problems more difficult to deal with.