AMTRAK NORTHEAST REGIONAL, EN ROUTE TO NEW YORK — Spending an hour-and-a-half immersed in the minutiae of retired Rep. Barney Frank’s day-to-day existence may sound like an odd way to spend a Sunday. But it’s part of the peek-behind-the-political-curtain cinephiles have come to expect from the intellectually challenging Tribeca Film Festival .  

Audiences will get their first taste of “Compared to What: The Improbable Journey of Barney Frank ,” later this afternoon.