NS RP Units

[sgtcarl1]

Well, I don't know much about anything, let alone slugs. But I can tell you that one reason NS uses them is to help the locos to pull the heavy coal trains from WV to the railyard in Salem to be sorted out. They use them in the railyard, and I have watched them work. I also saw a unit at CSX railyard that was helping an SD40-2 switch cars around. It was labeled RPD (RDP??) Slug.