The Underground Railroad was neither underground nor a railroad. It got its name because its activities had to be carried out in secret, using darkness or disguise, and because railway terms were used by those involved with system to describe how it worked.
Hydrolyzed collagen is collagen that is derived from bovine bone and cartilage. Usually, the bone is crushed, ground, defatted, soaked in acid to remove the calcium, soaked again to break the collagen bonds and then dehydrated.
A denatured protein is slightly different than both of these though. Denatured protein is also known as a whey hydrolyzed protein. When you hydrolyze a protein, what you're doing is basically changing the structure of the protein permanently. The peptide bonds that are present in protein are broken. However, despite the change in the structure of the protein, denatured protein still contains all of the amino acids that are found in other forms of whey protein. As a result, denatured proteins are still nutritionally beneficial.