The most used mode of transport in Poland to go from one city to another is train, not because they are fast, but because the roads are not good, and there's only a quick route across the country. One can go from one city to another in an adventure, crossing the country, which can take anywhere from 6 hours to 18! It all depends on your luck with the connections. It is best that you look on the web beforehand, and listed there are all train schedules and prices. I spent from 12 midnight to 3 am waiting for a train in a station with a couple of banks, no doors, very few people. But with a couple of guards.