I used to take the Amtrak Acela from Boston to NYC a few times a year for business travel and it was very enjoyable. I always looked forward to the ride, which is absolutely not something I would ever say about driving or flying these days. Comfortable, scenic, quiet, possible to work (or just relax and watch a movie) in your seat, reasonable food and drink available in the dining car. Step off the train and you're in the heart of the city.

That said it would be much tougher to justify if work wasn't footing the bill. A single round trip is up around $500 per person unless you are willing to leave at the crack of dawn. Doing this regularly, or with a family, would get prohibitively expensive for most people. I definitely wish rail travel was more viable and accessible in the US, it's got so much going for it.