One of the most important aspects of not only the underground railroad, but the freedom of the slaves as a whole was communication. On most plantations slaves were not able to talk to each other, let alone a slave from another plantation. So what I want to know is how they were able to have a secret communication in order to transport each other across the nation.
Slaves were not allowed to read or write. In fact it was illegal to teach them. So they had to find some sort of unspoken way to talk to each other. This mainly came in the form of codes such as song, dance, rituals, code words, and symbols. Codes were created by both whites who were aiding the slaves and the blacks who had already escaped.
One way of coded messages was the quilt codes. Making quilts was a African tradition that had specific meanings. In Africa they were used to record history and were passed down from generation to generation. Quilts would be hung over fences so that all the slaves on the plantation could see them as well as other slaves passing by. Each pattern represented a specific meaning. SOURCE (http://www.osblackhistory.com/quilts.php)
This was called the flying geese. Geese migrated north in the spring. Hence most slaves chose that time to escape to the north because they could use the geese to help them navigate, find food and water, and places to rest.
This symbol is called the monkey wrench. This was the universal symbol to gather all of the tools necessary to escape. Not only did this mean the physical tools but also the mental ones and spiritual ones. It took a lot of bravery to try and escape, for if they were caught, it was death or torture.
Obviously this is a sailboat. This symbols meaning is almost self-explanatory. If a slave were to see a sailboat that meant there was a body of water nearby or that a boat was ready for them to be picked up.
This was the wagon wheel symbol. This was probably one of the most important ones. Most slaves escaped on foot and on a wagon. Their journeys took a long time and therefore they needed to pack enough provisions to last. This symbols was meant for them to start collecting all of the necessary items in order to take on a long journey.
SOURCE (http://www.osblackhistory.com/quiltcodes.php)
These were just a few of the many symbols that were used. I found this video on YouTube and it goes over more quilt patterns that were used. I found it extremely interesting.
http://www.youtube.com/watch?v=T2VzlC-hOBA