I went on this excursion last year and it was fun. Last year, I think it was free and you had to make reservations on line. Anyway, we left from the south side of the station, went down to the 21st Street bridge, came back through the yard (we were promised a run through the shop building, but this didn't happen), then proceeded on the through track to the north side of the station, then continued to the end of Amtrak's trackage, then back through the station and arrival on the south side. There was some interesting narration. Superliner liner coaches and a lounge. Expect lots of kids.