Is it possible to enter Russia by train 1-1.5 hours before the visa validity period starts?

I wouldn't risk this.

I exited Russia with a friend. He had given the end date for his visa, by mistake, as the day we left Moscow. Travelling by train, we didn't reach the border until a couple of days later. They got that he'd made an error, but they were not understanding.

He was led away by armed guards. There was no explanation. The entire train was made to wait and we didn't see him again for something like four hours. We later learned he was detained in a small room, ostensibly waiting for various officials and translators, and questioned repeatedly.

He had to pay a very large sum of money to the guards in woolly circumstances. This was vaguely suggested to be some sort of administrative charge, but very soon after he handed it over, it became clear it was just a bribe. After which (and we're talking about a sizeable chunk of his remaining budget for the trip), they still refused to let him through. The rest of the train was sent on, and they forced him to wait several hours longer for a train going back in the opposite direction. He had to get off at the next city, then pay accommodation and expenses there for several days while waiting for a new visa to be processed, which obviously he also had to pay for.

Note that this was leaving the country — not even like he was trying to get inside the borders.

Note also that I'm not even really complaining about any of this, and neither was he. It was his mistake. It's border control: you need to take it seriously.

If your friend does this, she'll be at the mercy of the guards, who have every legitimate incentive, and several illegitimate ones, to ruin her trip. The smart decision would be not to do this!

I've been on a Russian train with a Canadian whose visa expired during the train ride (so just a couple of hours) as we crossed the border after midnight into Mongolia. Said passenger was marched off the train ("there is ... problem") and returned hours later with multiple fines and a black mark against their name.

Short answer: It's not worth the risk. Border guards are not known for their leniency and "I thought we could just wait" or "I didn't realise" is almost never an acceptable answer.

Let's think logically. Imagine one is a Russian border officer. One got a job during which each day got the stamp for the passport and visa checks:

As you can see, there is a date on it, and it's numbered (the stamp is adjustable itself, however is sealed, so officer can't change the date by himself). So there is no time there (this is important).

So back to our officer. He got a stamp, left a signature in some documents, and now is checking passports and visas. Likely the stamp for your friend will be done on the visa. So after that everybody who checks the visa and passport will see, that the visa is opened the day before it start date.

So there is a problem for our officer which could lost his job for such situation. More than that, it is a problem for your friend:

• if he'll try to get another visa, then there will be a trouble, as the previous one was opened the day before it starts
• if your friend accidentally being stopped by the police, they'll see that passport and visa, and they definitely will have a question: Why it is opened a day before it starts?

If I was your friend, the last (seriously), last thing I would wish is such question to me from Russian police, as the simplest explanation for them would be not I got train 2 hours before the visa starts but I got a fake passport and visa.

So, as others said, this is not a thing you should try. The only way your friend could get out from this situation without problems if the border officer in a good mood and he got a stamp with future date with him. This is as probable as to meet an elefant on Nevsky prospect in Saint-Petersburg. Maybe it ran away from zoo or you're on some festival, but in general this isn't that day.

Not that I am recommending it, but it happened to me. I received a Russian visa with wrong date on it. (Note to self: check visa for correctness in future). The boarder guard put a stamp on it like VMAtm described, without further comments. No one noticed on departing the country, either. Now I have a cool visa in my passport with a stamp, and not even the year matches.

On other trips, i found that the Russians have very tight border controls, not only on entry, but also on exit.

I would not risk it.