The underground railroad was a network of secret routes and safe houses through out the United States in the early to mid 19th century.  It was neither under ground nor a railroad but the African-American slaves used it to escape to free states or to Canada secretly.  When escaped slave finders couldn’t find the slaves they thought that they somehow caught a train underground and escaped. Harriet Tubman was one of the conductors, people who helped over 100,000 slaves become free.  One of the songs they used to get to freedom is “Follow The Drinking Gourd”.  Songs were used instead of maps because if a slave was caught with a map they would be heavily punished.