Your answer is) People have become more interested in protecting wetlands than they used to be.
this is what I got from Google-
When the U.S. Supreme Court ruled in the Dred Scott decision that the Missouri Compromise's prohibition of slavery in territories was unconstitutional, an increasingly diverse body of opponents of slavery rallied around the Republican Party.
Primarily alternative way that these railroad companies used their land was to either sell it or rent it out to private business, and occasionally individuals, since the rail companies did not always need all the land they were given for development.
