Changes

The regional train (S-Bahn) is great (it even goes out of the country), it has A LOT of stops, which means that you can easily jump off. If it has only one floor then you can see the inspector from a large distance, which is helpful. Sometimes there's only one inspector, or, if you get less lucky, several. Other  Interregional trains are bad; the inspector checks tickets have several inspectors that check several times during the trip -- by memory or, sometimes, by asking out loud who just got on the train. If caught without a ticket, you'll usually be asked to get off the train on the next stop. There's no such thing as station security, so you'll easily be able to jump onto the next train going your direction. The cops are not liberal.