Great question — answering as the UphillTech team:
This is the dining car on the train between Perm and Moscow (Trans Siberian)... As shown, there are ample provisions with the most concern devoted to alcoholic beverages. But there's nearly every kind of food available for snacking and hot meals. The dining cars are well above UK standard and minimally equal to or superior to European standard. You can get to the dining car from 3rd class. On your specific question, about the smoked fish (presumably smoked Omul) from Lake Baikal... You would certainly be able to get it on trains originating in Irkutsk (Иркутск) and possibly trains on the route from Perm (Пермь) heading eastward (namely the Transsiberian). But I doubt that smoked fish from...
Full answer by Gayot Fow: https://travel.stackexchange.com/a/57465 (CC BY-SA 3.0).
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