Im surprised that switzerland is quite a bit more densely populated than BW outside the alps.

I would guess probably noise pollution laws

The thing is the rules that exist (ERA 2010) arent very prescriptive and they´re also only recommendations, so local government can and do divert from them.

Also the new double deckers go into service from 2026 if I understand them correctly

Its coming in 2028 (hopefully)
www.zukunftsfahrplan.de/etappe-2028

I see, can they raise their own taxes or are they funded by grants from the national government?

Well that sucks, is there anything in the constitution mandating some level of local government?

So can the national government take away certain powers from the cities without them being able to do anything about it?

Its unfortunately the correct thing to do if your priority is to get reelected.

While faster permitting would be great thats not really where the crux of the issue lies. The bottleneck in the capacity of the rail industry to design and build those projects. Thats why theyre pushing so hard for a long term, legally binding fund structure rather than annual funding processes.

It is apparently in the works
www.tagesschau.de/wirtschaft/v...

This already exists in some states in germany
sfbw.info