#11 - SILVER/PALMETTO
New York to Miami - The boring east coast, using antiquated single-level equipment because the Superliners wouldn't fit through the Baltimore tunnels and because it would be a waste to use them on these runs anyway.
#10 - CRESCENT
New York to New Orleans - It skirts the mountains so it's not much better than the east coast trains.
#9 - LAKE SHORE LIMITED
New York/Boston via Buffalo to Chicago - Very nice east and south of Albany through the Hudson Valley and Berkshires, but that's about it.
#8 - TEXAS EAGLE/SUNSET LIMITED
Los Angeles via San Antonio to New Orleans/Chicago - Some nice desert and double decker Superliners. Takes even more forevers than most Amtrak runs.
#7 - CITY OF NEW ORLEANS
Chicago to New Orleans - Amtrak didn't rename it thus until after the Steve Goodman/Arlo Guthrie song about the Illinois Central train that preceded it. The Mississippi bayou is nice.
#6 - EMPIRE BUILDER
Chicago to Seattle/Portland - Overrated in my estimation. Ratio of scenery to distance is low. Hits Glacier Park in the dark too often, and misses the best part anyway.
#5 - CAPITOL LIMITED
Chicago to Washington DC - The great Pittsburgh skyline and lots of great river valleys from the Ohio to the Mon to the Youk to the Potomac, and as much of Lake Erie as you need to see, and it uses Superliners too.
#4 - CARDINAL
Chicago via Cincinnati to New York - Extreeeeemely slow, even by Amtrak standards. Lovely trip over the Appalachians and the USA's most impressive view under a bridge through the New River Gorge. The Ohio River is the best river to see at night with chemical plants and bridges all lit up and Cincinnati has the best skyline view for a city of its size. When the route was extended from DC to New York, the Superliners were given to the Capitol Limited, which had just had a huge train wreck near Rockville.
#3 - CHIEF
Los Angeles via Kansas City to Chicago - Amtrak's fastest long distance train, but still slow. The highlight is the mountains north of Albuquerque to Trinidad, Colorado.
#2 - COAST STARLIGHT
Los Angeles to Seattle - The super-highlight is hovering right over the Pacific coast north of Santa Barbara on land preserved au naturel by the U.S. Air Force, and then climbing inland to San Luis Obispo, so you can get the same thrills from the local Surfliner trains. It hits NoCal's spectacular Mount Shasta at night, unfortunately. Try to schedule for a full moon.
#1 - CALIFORNIA ZEPHYR
Chicago via Denver to SF Bay Area - This is the one you must see before you die, at least between Denver and Glenwood Springs, although once you get there, I defy you to leave the train. The climb and descent west of Denver could probably be rivaled by the Space Shuttle experienced only in slo-mo. And then west of the continental divide, it follows the Colorado River nearly from its source, including many miles where the canyon is only wide enough for the river and you. I think I left my jaw back on the track. From there into California, the deserts and high Sierras would be fantastic enough even without what came before.