The only place I've ever seen them is during an Amtrak stopover in Pittsburgh early in the morning while switching from the Capitol Limited to the Pennsylvanian.
The picture to the right is a photo of Silverliner I 246 located at the Railroad Museum of Pennsylvania in Strasburg, PA.
East of Cleveland, the roadrailers take the PRR route through Alliance and Pittsburgh. They haven't run the lakeshore route regularly since the Conrail days.
A few years ago, in the aftermath of a wreck in the Beaver valley, NS detoured roadrailers up the NKP to Ashtabula and down the Youngstown Line. Here's one of those detour trains, southbound at US 322: http://www.youtube.com/watch?v=YhcVsm1SOaQ
A few weeks ago, I saw one rolling through Logansport, IN. on the old Wabash route. I'm not sure where it would have ultimately gone, but I'd guess Decatur, IL or beyond.
When it's a tie at the railroad crossing, you lose.
we have a pretty big Triple Crown section in the Calumet Yard in IL, we take one train to UP's Proviso Global 2 Yard and one train goes out East somewhere