If you're not traveling between those specific destinations it can take far, far longer. Amtrak is a joke.

Amtrak is decent on very specific routes and still an absolute joke to anyone who has used trains in Europe, Japan, Taiwan, etc, and no personal experience but I'd imagine China too. My friend takes the Amtrak route up and down the Pacific coast precisely because she's stuck on a train for days and can't be disturbed while doing boring paperwork as an anti-procrastination strategy. Although the observation cars do have great views.