it's simple. The rails in the railroad was layed down on a road.
The Underground Railroad. The Underground Railroad.
The Underground Railroad?
underground railroad
Central Pacific Railroad.
The Chicago and Galena Union Railroad
The Central Pacific Railroad was first built in Sacramento, California. The Central Pacific Railroad is the former name of the railroad network that formed part of the First Transcontinental Railroad.
It is not named for a state but for a railroad of the same name.
Only if your talking about a name or a pronoun.
Railroad
That would be a "trestle"
underground railroad
it came from a railroad