An automated high-speed freight train is controlled by an onboard system. In an emergency, the system undergoes a processing delay before applying the physical brakes, during which the train travels a "reaction distance" (analogous to thinking distance). Once the brakes are engaged, the train travels a "braking distance" before coming to a stop.
Explain the factors that affect the reaction distance and the braking distance of this automated train.
Write down the equation that links distance, force, and work done.
The kinetic energy of the train is fully dissipated by the brakes as work done during stopping. The work done by the braking force to bring the train to a complete stop is 135 MJ135\text{ MJ}135 MJ. The average braking force applied is 450 kN450\text{ kN}450 kN. Calculate the braking distance of the train, giving your answer in metres.
An extremely large braking force would result in rapid deceleration. Explain the possible dangers to the train, its mechanical integrity, and its control from such a large deceleration.