Which best describes a development that improved railroad safety? A. Railroads adopted standard time to coordinate schedules. B.
Railroads offered fold-down beds so that people could sleep more comfortably. C. Companies standardized track technology so that they could use each other’s tracks. D. Companies replaced hand-operated brakes with air brakes on trains.
Option: D. Companies replaced hand-operated brakes with air brakes on trains.
Explanation:
In the early period, trains manually stopped by involving in hand-operated breaks. The handbrake worked by handling large wheel in the coach, attached to chains and levers which set brake pads under the train. To improve the safety of the rail coach, air breaks replaced because they were much more powerful and reliable, than the manual one.
The correct answer is option D. "Companies replaced hand-operated brakes with air brakes on trains". The development of air brakes on trains was a significant improvement of railroad safety. Air brakes function much more faster than hand-operated brakes, because hand-operated brakes required that the brakemen turned the brakes in one car and jump to the next to set the brakes on, and so on.
Overproduction was one of the main causes because people were producing so many resources that the demand for them went down. Because there was no longer high demand, prices went down which ultimately weakened the economy of the United States.
Throughout the Ming dynasty, there was a war between the Mongolian tribes. So in order to keep them out and defend their territory, the emperors of the Ming dynasty used alot of their fortune to keep things stable against invasions from the Mongolians. <span />
