I was going to travel to Moscow today by car (followed by a trip to Kazakhstan and Kyrgyzstan before returning to Russia via Siberia. I have a visa valid for two entries. However, we're currently stuck in Rezekne, Latvia, waiting for some paperwork to finish. This may or may not be finished tomorrow, and I would like to travel on as soon as possible. I see that there is a train from Rezekne to Moscow leaving tonight.
Can I take the train, instead of going by car? Would this cause me any trouble later during the trip, especially regarding visa issues?