In this small town on the upper Mississippi River, where railroad tracks slice the length of the community, and freight horns seem as common as bird song, residents fear that life is about to get more dangerous. David Maze, who has lived happily and safely in Camanche, Iowa, since birth, is worried that the trains that roll not far from his clapboard house could one day kill him, or his neighbors, and cause his town of 4,300 residents to suffer. His concern is the concern of many here: If a proposed $31 billion merger between two powerful rail companies — Kansas City Southern and Canadian Pacific Railroad — receives federal approval in early 2023, the number of so-called “monster” freight trains rumbling through the town each day will triple. Instead of five to 10 trains per day, the merger is expected to bring an average of 21, perhaps more, many of them heavier and at massive lengths. Camanche is not alone. Cities and small towns stretching from Houston to Chicago are similarly af...