You can read the story, here
Basically, these trains are the victims of high-speed train travel, low-cost airfares and general improvements in cars and motorways…there are just too many alternatives.
Still, this is a great shame. Overnight travel was certainly easy and convenient – you go to bed in one city and wake up, the next morning, in another. It’s centre-to-centre too. So, you didn’t waste time getting into town.
The whole experience was civilised, sophisticated and romantic; even in economy class. Actually, especially in economy class.
The sleeper train made the subconscious association between railway travel and dreaming absolutely explicit.
The high-point of the continental sleeper service was the period between the wars…when the service was provided by La Compagnie Internationale des Wagons-lits. This was a separate train company that provided high-class sleeping berths and restaurant cars to national train companies. A bit like Pullman in the USA.
They advertised their premium service by commissioning posters by the greatest designers…