Attempting to ride or hike on, or even walk near train tracks, bridges, and trestles is dangerous because you may:

The correct choice emphasizes the serious danger posed by being near train tracks, bridges, and trestles: being hit by an approaching train. Trains are large, heavy, and move at high speeds, and they cannot stop quickly. This means that individuals who are on or near the tracks are at a significant risk of injury or fatality if a train approaches.

While being yelled at by a train conductor may happen, it does not capture the life-threatening nature of the situation. The primary concern should always be the potential for physical harm from an oncoming train, and it is this grave risk that makes it essential to stay away from these areas for personal safety.