pass car deliveries delayed

From Railway age::

Silverliner - 5 car deliveries are behind and is causing MBTA’s order for bi-level cars to be delayed 18 months.

One has to wonder if this is a harbinger of other manufactures deliveries to Amtrak and other agencies as well. Wonder what the delay is ?? Is it assembly ( skilled workers ); could IT be steel and / or Aluminum; or is it components ( I would suspect all aux equipment to be common to all cars ?? ) Could be a combination ??

http://www.railwayage.com/index.php/passenger/commuter-regional/mbta-railcar-deliveries-behind-schedule.html?channel=