The underground railroad was a bunch of people that helped the slaves escape to both the north and to canada. This consisted of many individuals, a lot of white people but mostly blacks. The south lost 100,000 slaves between 1810 and 1850 because of the Underground Railroad. Sometimes, there was a conducter that would act as a slave to guide the others north.
They would move during the night, hiding in barns and other places out of the way.