 The numbers of the fire companies are all "dead" numbers in the  Chicago Fire Dept. Engine 17, Truck 46, Engine 24, Truck 6 (now back  in service as of March of 2004), & Engine 33, (referred to, not  actually seen in the movie), are all out of service. The Chicago  Fire Dept. has 24 battalions, battalion 25 was created for the  movie.