Tom,
I was hoping you saw this topic and/or the show. The category was State Capitals. The clue was, "Seen here is a train on this railroad whose name includes two state capitals and a third city."
The first person said, "Burlington North Santa Fe." The second said, "BNSF....Burlington," before being cut off by Alex Trebek. Third didn't hazard a guess. (I know this conflicts a bit with what PRR1950/Chuck posted, but I recorded it so I'd have the clue and the answers.)
And Jim Berger hit the nail on the head - last two days, contestants have missed a lot of questions.
David