How did the steam locomotive change people's lives?

Answer 1

In MANY ways.

First, it became possible to move mass quantities of stuff like grain or fruit quickly and inexpensively from one place to another. For example, shipping food from the farms where it is grown to the cities where it is consumed. As a side note, railroads first shortened, and then eliminated, the American "cattle drive" of cattle to market.

Second, it became possible to ship ANY sort of consumer goods from one place to another. Railroads made Sears Roebuck possible; people who lived in the country on farms could write a letter and buy stuff from stores from anywhere in the world, and have it delivered by rail.

Third, and perhaps most importantly, railroads allowed "hybrid vigor" to work on the human species. You no longer had to marry the girl or boy from the same village or the next village over; it became possible to go someplace else and marry somebody with practically NO genetic connection to you.