Nope - the newest lines (Victoria, Jubilee) are all smaller diameter trains. The larger, squarer cut+covers (District, Circle, Metropolitan etc) are generally older, because you can't cut a trench across London for a new Tube line any more.

It's still not hard to stand on any of the trains as long as you're not right beside the door on a Tube (unless you're extremely unusually tall, but the odds are well against that).