That Sightseer isn't in a position that indicates it's in service. It would be between the Diner/Lounge and the coach if it were.Upon reviewing the railcam at Chesterton, IN tonight, I saw that the #30 headed to DC (6/14/23) had the lounge car added to the end and included the cafe car as well.
View attachment 32855
(Plus, the phase III leading unit)
It is probably a deadhead, although for the life of me I cannot figure out a reason for a Sightseer to be deadheaded to Washington. If they were adding them to the consist, they'd just start dispatching them out if Chicago in normal, in-service position and letting the first 29 with an SSL be the return of the first 30 consist with it.