You can't do that even in London. Unless you're luck and you're getting on at a terminus station and there's seat available. If you absolutely need a seat you

You can't do that even in London. Unless you're luck and you're getting on at a terminus station and there's seat available. If you absolutely need a seat you can always let the first train got if there's no seats depends on haw important it is to get a seat for you. Of course if you avoid peak hours which we can it's a different story.