That was my first question, do you know exactly what positions that you're interested in? I mean there's everything from the center manager you probably hate, to being a driver trainer or feeder instructor. LP apprentice/detective. Safety dept. On-road supervisor. Assistant service center manager.
I always recommend LinkedIn as a valuable tool for identifying people in positions you are interested in, and seeing the path they took and how long and what credentialing they had when they got it. You could even message the person and ask about the position in particular; anyone who creates a LinkedIn is willing to answer questions, it has a Messenger type feature