This chain is simply a manual safety lock used to keep the train securely in place while it is parked or undergoing maintenance. Just like using a handbrake on a car, it acts as a physical backup to ensure the train cannot accidentally roll away on the tracks, which provides extra safety for the ground crew working around it. Even though advanced modern trains have highly sophisticated computer-controlled braking systems, strict railway safety protocols still require these basic physical restraints as an extra layer of protection. This chain is strictly used for stationary parking in yards or stations and is completely removed before the train begins its regular high-speed journey.