So it is all about collector shoe problem. The power failure and damage to the rail tracks were caused by the collector shoes. And the trains have been running for 24 years without major breakdowns or this kind of frequency until these few days.
Logical deduction, simplified, is that the collector shoes have reached their operating lives and need to be replaced as they were working fine for 24 years, only starting to fail.
Another deduction, the shoes have recently been changed. If that be the case, either the new shoes were installed wrongly or the new shoes were faulty.
And better beef up on the standby power system and test them on a fully packed train and see how effective is the ventilation and how long it will last. This is critical as it can be deadly.