Slavery.

i know you're wondering, what railroad? Well the simple fact is that everybody has heard of the Underground Railroad, but not everyone knows just what it was. Firstly, it wasn't underground, and it wasn't even a railroad. The term "Underground Railroad" actually comes from a runaway slave, who while being chased swam across a creek and was out of the owner's sight. The owner said "...must have gone off on an underground railroad." That man …

…often took up similar jobs in the North. The need for the railroad slowly began to decrease as the fight for abolishment grew stronger. It was no longer nesscary for the raliroad to be, since almost all the slaves who were going to run already had. The final motion that brought the railraod to it's final stop was the signing of the Emancipation Proclamation by Lincoln, ending all slavery in our now free country, forever.