Originally Posted by
madfish
Just remember your Russian visa.
Also, since you talked about taking a train from Helsinki to Russia, pay attention to the dates when your visa is valid. The Helsinki-Moscow night train is somewhat of a visa trap because some people forget to check on which side of midnight you check the border and either try entering the country half an hour before the visa becomes valid, or exiting eight hours and a half after the visa expired. This is not something you would want to experience.