Apparently it's a different thing: https://www.ozon.travel/help/railway/preparation/trains/ https://www.ozon.travel/help/railway/preparation/trains/ As far as

Apparently it's a different thing: https://www.ozon.travel/help/railway/preparation/trains/ https://www.ozon.travel/help/railway/preparation/trains/ As far as I understand, М has private bathroom but СВ doesn't. It's confusing but I'm sure I saw them sold at different prices.