The%20three%20industries%20of%20Railways%2C%20Atomic%20Energy%20and%20Defense%20are%20reserved%20for%20operation%20and%20management%20by%20the%20public%20sector%20or%20Government%20only.%20This%20is%20because%20of%20the%20need%20for%20security%20and%20secrecy%20to%20be%20maintained%20especially%20in%20the%20functioning%20of%20the%20Atomic%20Energy%20sector%20and%20Defense%20of%20the%20country.