I was at dfw once, and the skytrain would not move, an agent showed up reasonably fast and rectified the problem. When I got to my departure gate the agent was "annoyed" that I had not responded to her pages looking for me--my upgrade had cleared (and the flight was getting ready to leave)--I don't think she believed my explanation: "the skytrain was stuck".
PS: My cellphone battery was "dead" so I couldn't call the EXP desk.