Answer:
The answer should be: Companies replaced hand-operated brakes with air brakes on trains.
Explanation:
You have to think how hard it was for trains to stop with hand operated brakes. Trains go fast, and not stopping in time can be dangerous. Hope this helped :)
That they were just a bunch of hippy s and the purpose they do this all for is not what they do it for but yet do they no there wrong there trying to get more people to like classical music and raise the rate of more people liking old timey music in stead on hip-hop and rap even though those kinds of musics are good they still want more people in the classical sisitty. hope i helped :)
