I want to understand this question, first of all, I have to ask whether heroes created history or history created heroes. Like many questions, the answer may not be A or B, but AB multiple-choice questions. There are heroes who are pushed by the historical trend and heroes who change the historical trend. And this part of the hero who changed the historical trend and led the movement may be the revolution. Of course, for history, the material preparation for change may be the accumulation of decades or even hundreds of years, which is an opportunity to trigger qualitative change.

So I personally think that "revolution is the locomotive of history" has two meanings. First, the revolutionary movement may change the track of historical operation from the direction; Second, the material preparation of the revolution is the fuel and power to push forward the history.