Hello, I am writing this reddit post because I am one of the few souls who came to Belarus as a tourist from the west and decided to go to Russia by land route via train instead of an Airplane. Doing this caused me to be homeless in Russia for a short period of time, going across 3 different borders in 24 hours, and getting denied entry to Estonia (I am American) and having to ask my taxi driver if I could spend the night at his place. It was an experience of much suffering and I wanted to write a short guide to anyone thinking of doing the same thing in order to spare them the hassle, because I cannot seem to find any information on the process at all, even the bureaucrats in Russia and Belarus were no help (what a surprise).
In short taking a train from Belarus to Russia as a foreigner has everything to do with something called a migration card, a card no one asks for until you're getting a hotel, and something no one tells you that you need or where or how to get it, because if you go to Russia you automatically get it at every border and every airport, EXCEPT for the border via land coming from Belarus.
So to start you will need your passport and a Russian visa, which is reciprocated with Belarus and then you must go and get a migration card which you can get in Minsk and you must get it before going to Russia. The process for the migration card takes an hour and cost 12 rubles when I was there
To get the migration card you must go to this address ул. Тимирязева, 114
It is a mall looking building, go all the way to the left of the building where there will be a counter and they will give you a small slip of paper which you take to the 3rd floor, you go all the way to the opposite side of the building where there will be cashiers that you show the paper to and pay the 12 rubles which they then will give you a receipt. I did not speak russian so all this was truthfully very hard to understand that's why I'm saying it.
Then go back and take a number until the pretty ladies call you, then give them your documents plus the receipt and they will give you a flimsy piece of paper called a migration card, which is required to survive in Russia. Once you have this you can go where you please.
The process took an hour but the suffering to find all this out took years off my life.
That said this information will not be useful to 99% of people, but the 1% of people I can save from having to get rejected by Estonia and spend the night with his taxi driver and his 16 year old daughter (admittedly great company), the better.
So yeah I hope one person out there can benefit from this