In Soviet Union... well, I'm not actually sure what were the rules for having a dining car on a train, but all trains I rode had one. And I was very poor. So

In Soviet Union... well, I'm not actually sure what were the rules for having a dining car on a train, but all trains I rode had one. And I was very poor. So poor I couldn't always afford a ticket. But, the system worked differently. There were "coupe" cars: the car is divided into small compartment for four people each. Each compartment has a door, a table the four have to share. Two double-decked beds. Upon request fitted with a hammock-like net that served as a crib. Then there were "platz-kart" cars: similar idea, but six people per compartment. No doors (you could see into compartments adjacent to yours). These also had "third floor" of beds (so, potentially could house nine people, but the top floor didn't have padding and was originally designed for luggage). Then there were "common" cars: these were usually the same as "platz-kart", but the third floor counted as a legitimate sitting place. Then, as times got worse, the "common" class of cars became more prevalent, and sometimes these would be repurposed short-distance train cars that didn't have any place to sleep at all (just chairs, like on a plain, or wooden benches). Any train had all kinds of cars, what was different was the proportion (as Soviet Union was headed towards its collapse, there were fewer and fewer "coupe" cars and more "common" ones). But, even in the worst times of the late 90's there still were dining cars. At some point train stuff stopped serving tea, which was the hallmark of any train travel: it came in special cups with heavy steel holders and with two bricks of sugar with the picture of train... In my last visit to the dining car, the only dish on the menu was pelmeni (Russian-style wantons) with vinegar (a more upscale version is served with sour-cream) and vodka for dessert... Even by the standards of the day it was sad. But, hey, they still had a dining car!