I'm a UK passport holder planning to travel by train from Warsaw to Moscow via Minsk next June. As I have a little slack in my time table, I'm thinking of catching the sleeper from Warsaw to Minsk one night, followed by the Minsk to Moscow sleeper the next night. This will give me a day to explore Minsk. Can I do this with a transit visa? Or will I then be unable to leave the station? (If it affects the answer, the two border crossings -- from Poland, and to Russia -- are unlikely to be on the same day.)
Yes, you can leave the station. The period of validity is said to be two days on their official embassy sites in both the US and UK, so you should be okay leaving the next day.