Once again, the Silverliner V cars are being delayed due to production issues. More of the typical problems, such as design flaws, workmanship issues, and labor relations problems, are holding up the cars even longer as the aging Silverliner IIs and IIIs struggle to make their runs.
More info here in this Inquirer article: http://www.philly.com/philly/news/local/20110524_Delivery_of_new_SEPTA_railcars_lagging.html