There’s the Trans-Siberian Railway, Beijing to Moscow, takes seven days I think. I knew a guy who rode that. Sounded uncomfortable, but he enjoyed it.
For true luxury, there’s the Eastern & Oriental Express between Bangkok and Singapore. (Actually, I think it goes as far north as Chiang Mai.) Too rich for my blood. And I don’t even know if it’s running anymore, as Covid has shut down a lot of Southeast Asia.
I have bee on three train trips in Africa, of 40-50 hours.
– Dakar - Bamako
–Wadi Halfa - Khartoum
–Kigoma - Dar es Salaam
None of them are trips that anyone would do for fun. I rode on them on the 70’s, and it is possible that they have been improved, but I wouldn’t bet on it. First-class may be OK if the carriages have been well-maintained. Of course, I rode 3rd-class, on hard wooden bench seats.
Dakar-Bamako would be a nice trip, if you had any comforts. There were several treasured memories from that trip. It was the trip you get a true sense of Africa. But those comforts might insulate you from the true adventure.
I did the Trans-Mongolian, not non stop. But, although i had “first class” cabin. It was not a luxury experience by any means. Just a private compartment with a little better bedding. Bring some food with you.
Or there’s the Rovos Rail Cape Town-Vic Falls 7-day trip.
In 1987 I traveled by train from Juarez to Mexico City, then back again later. That was 36 hours each way. Thoroughly enjoyed it. I was in the sit-up seats, but they did have sleepers. Whenever we stopped for a while at a station and passengers got off to stretch their legs, I would chat with this fellow American who had one, and he seemed to like it just fine.
‘Hotels on rails’: Plans for new network of European sleeper trains unveiled
Heh. When I was traveling around Europe in '86, I spoke with a fellow traveler who had a Eurail Pass and used it to sleep every night on a train. He zigzagged between northern and southern Europe, spending a day at a destination before climbing aboard another train to snooze away the night. I guess he did not mind sleeping sitting up each night. Ah, to be young again.
Bumped.
Just the thing for a train trip in chilly November?: https://www.victoriantradingco.com/item/99-by-9933082/category/pullman-blanket
This train sounds amazing.
That reminds me of Japan’s Shiki-Shima train. If you watch the Amazon series James May, Our Man in Japan, May rides it in one of the episodes (where he makes a major faux pas in the dining car).
Yes, I mentioned that one earlier this thread but did not have a link. You need some deep pockets for that though.
I can dream… 
The California Zephyr is supposed to be on a par with the Coast Starlight - we’re doing both next May (CS from LA to Emeryville, CZ from Emeryville to Chicago).
International: Go to Australia and take the Ghan or the Indian Pacific. There’s one in South Africa (the Blue Train). Here’s an article talking about long train journeys.
I’ve been watching loads of train videos on Youtube, and there’s a train from Winnipeg to Churchill, MB (Churchill’s only ground transportation). I’d love to do that some time to see polar bears. The scenery en route doesn’t seem that exciting, but once you get there… It’s not all that long, distance-wise, but takes most of 2 days and nights.
On that list, I’ve taken The Canadian–believe it or not, three times.
First trains leaving Paris in 2024. Might have to wait a while. Looks like it might be nice, and would a good alternative to traveling around Europe.
Not a multi-day trip, but the Nightjet is expanding their services next week.