But they are not double-deck - I only spoke of double-deck here. (The bulk of S-Bahn traffic is indeed done by single-deck class 420, 422, 423, 424, 425, 426, 470-474, 475-485 EMUs, and some others are in regional service only.) There was one double-deck EMU in Germany, the class 445 prototype, but DB did not purchase it. I could never find out the reason; it should not have been a technical failure, given that the SBB RABe 514 was based on it; so, it was probably price.

_{*Lunatic*, n.
One whose delusions are out of fashion.}