DB: “What do we do about all our international trains being too full in summertime?”
Passengers: ”Run more of them, or more carriages?”
DB: “Ah no. We’ve not got any extra, and half of what we have are broken anyway. So let's make them compulsory reservation - and keep passengers away. Genius!”
(oh and half of them are going to break down and be filled to the roof *anyway*)