[hobofan]

There is no mystery of what's the cause here. That is widely known and reported.

It's lack of maintenance / modernization on the rail lines. This is 100% a political failure. If the money would be allocated towards that, the problem could be fixed in a few (IIRC 5-10) years.

Of course in addition towards that there is the additional political failure of wrong incentives which creates mechanisms like the "Pofalla-Wende" (delayed trains turning around mid-journey, so that the back journey doesn't count as delay) to game the bad statistics.