Which impact did the steam engine have on railroad travel

A. It eliminated fires in the engine

B. It allowed trains to carry large loads

C. It prevented train wrecks

D. It allowed trains to travel up river

I think the answer you're looking for is B

A steam engine is a heat machine that uses heat-steam energy as a pushing force that moves the piston back and forth in the cylinder and thus converts into mechanical energy. In order to get water vapor, it needed fire, so the fire was in the machine, but controlled. The steam produced in this way, and its conversion into mechanical work, allowed the release of a large amount of power, which was used to carry large loads.

The answer is: B.