The dynamomter equipment, part of which is seen in the wooden case, was transferred from a 1907 wooden car. #30 was jointly owned by llinois Central and University of Illinois (which provided equipment) for testing steam locomotive pulling power.
The dynomometer car had sleeping and dining areas for the staff who manned the equipment during testing.
This converted passenger car houses the dynamometer equipment for testing steam locomotive pulling power.
A National Museum of Transportation information sign posted near the IC/UI dynamometer car #30 display.
I've seen a couple of these in service on NS, good for track work.