With regard to points 3 and 4, it's not uncommon for engineers and conductors to be unaware of an issue with a train car on a long train, especially at residential speeds. A truck (the wheel set of a train car) can be in the dirt (off the track) and the crew would be none the wiser until they hit a track sensor, or people manage to wave them down about it.

Dispatch, if they knew about it, would not advise that they maintain speed, as that would risk further derailment. There is no problem solving on the fly. And all trains do have proper braking systems, but no train can stop on a dime with tonnage.

With regard to points 3 and 4, it's not uncommon for engineers and conductors to be unaware of an issue with a train car on a long train, especially at residential speeds. A truck (the wheel set of a train car) can be in the dirt (off the track) and the crew would be none the wiser until they hit a track sensor, or people manage to wave them down about it.

Dispatch, if they knew about it, would not advise that they maintain speed, as that would risk derailment. There is no problem solving on the fly. And all trains do have proper braking systems, but no train can stop on a dime with tonnage.