https://www.nytimes.com/2022/07/18/travel/amtrak-california-zephyr-train.html

Those are either the cleanest windows I’ve seen on an Amtrak, or she’s got an amazing filter.

(I’ve taken this trip and it is amazing. Get a sleeper if you can. Stop off in Omaha and Denver. If you stop off in McCook NE, the rental guy might leave a car in the parking lot for you. Also, this place is awesome. Why one might stop in McCook is an exercise for the reader.)