Been following the new line pretty closely. I was there for the arrival of the first Charger equipped test train.

There was no issue with the Chargers. There is an issue with the Series 8 Talgo trainsets. Their doors/steps have a sensor looking for obstructions. For some reason that apparently is only known to the inner circle of Sound Transit, the main 2 tracks are lower by about 8 inches than the main 1 platform. The series 8 cars see the higher platform of main 2 as an obstruction and won't open the doors.

The solution that was being worked on was a software fix. Until that is resolved Mater and his series 8 trainsets will have to use main 1, complicating an already very complex and tight schedule.