I missed your explanation of why the underground railroad was underground in the north. Maybe it will come in the next revision of history.
If a hero is made of someone who was responsible for the death of millions in Cambodia, it won't be making any new history.
The Underground Railroad, a vast network of people who helped fugitive slaves escape to the North and to Canada, was not run by any single organization or person. Rather, it consisted of many individuals -- many whites but predominently black -- who knew only of the local efforts to aid fugitives and not of the overall operation. Still, it effectively moved hundreds of slaves northward each year -- according to one estimate, the South lost 100,000 slaves between 1810 and 1850.
http://www.pbs.org/wgbh/aia/part4/4p2944.html