What best describes a development that improved railroad safety?

First of all, you dont have the answers.

But the answer is "Companies replaced hand-operated brakes with air brakes on trains" is the best answer because this stopped many of the fatalities that were caused by brake failures." which is I say on what you are using D

Yes,you are right Air Breaks are the best answer

hope it helped.

unknown. best bet to watch it is at kissanime (a lot of popups and has ads and has potential to be a virus not recommended) or crunchyroll (recommended but has ads and has no popups). you will have to wait. i really want netflix to give the other seasons.