The CDU never invested in the necessary maintenance, so from 2022 to 2025, SPD, Grüne and FDP had to push through funding all the necessary repairs and modernizations at once, crippling the whole network for the next 10-20 years. Part of it is beeing modernized while the rest now has a higher demand than what its capable of. Since the network is already very tightly packed, one small incident can cause a domino effect of trains beeing late throughout Germany.