Actually the locomotives are about 6 weeks ahead of schedule. The stations are the delay right now. The south station interior is practically bare and the North Station is just massive in scale with loads of work to be done. On top of that there are issues within the North Station in regards to an incorrect type of brick install. Material, workmanship, quality, or appearance not sure but regardless it has to be all ripped out and redone.
Gringotts is the issue, and its a serious issue. I'm confident that they will find a way but whispers of a delay stem from this behemoth and its programming issues.