We're going to Moscow and St. Petersburg (along with Helsinki and Tallinn) this winter, and considering our options for getting around. I'd rather not fly between the two cities in Russia, so we're debating the overnight train (Grand Express or Red Arrow for the experience) or the day high speed train.
If you have taken either, I'd love some input on which you would suggest, or pros/cons of each. Or any alternatives we haven't considered.
I took an overnight train from Moscow to St. Petersburg 5 years ago. I have no idea which line it was, I just remember that it was a PITA to book. I wasn't able to do it online and when I went in person, it was all Russian only. A friend of a friend in Moscow was kind enough to help me. Maybe things have improved online since then.
I ended up in a sleeper car with 3 Russian men. They were very nice and respectful, but I wasn't very happy with the situation. I barely slept.
Apart from the mixed-sex sleeper car situation, the trip itself was fine and not so different than other overnight trains in Europe. I probably would not do that trip by day as it's pretty long and there doesn't seem to be a whole lot to see on the route.
I was in Russia a few months ago and traveled from Moscow to St. Petersburg on the Sapsan (high speed train). Our hotel was across the main street from the train station (and our St. Petersburg hotel was walking distance from the metro), so it made more sense to take the train versus flying. We could have taken the early morning train, but my husband had a work meeting so we took the one in the afternoon (I think it left around 1pm). We couldn't book tickets on the website so the local office manager arranged it for us (your hotel can probably help you with this, we booked ours the day before and they couriered them to the office the morning of departure). There wasn't much to see during the 4 hour ride, but the whole experience was hassle-free.