It's the classical combo of poor budget and conflicting budgeting with aging infrastructure and bad management. DB was privatized 20, 30 years ago, but parts of

It's the classical combo of poor budget and conflicting budgeting with aging infrastructure and bad management. DB was privatized 20, 30 years ago, but parts of the infrastructure is public property and managed by the state. So DB willingly let rot them until the state will start renewing, which does take ages of course. At the same time, DB also started saving significant money, because that's what private companies are doing, so they removed parts of the infrastructure, which later started harming the planing on a nationwide level. And on top of this, there are parts of the infrastructure which are literally up to 150 years old, but still in use for whatever reason. Or in other words: classical underfunded, overused legacy system showing its age.