I spoke to Lionel customer service. They are well aware of this issue & apparently still doing corrective fixes - gratis, despite the cars being just past warranty. If you have any of these cars, call Lionel customer service, give the product number; 6-35250, explain the unwanted light blinking (the lady I spoke to knew right away once she entered the number).
They'll provide a return authorization number. I offered a copy of my receipt, but was told it wasn't necessary. Customers, however, must pay for return shipping. Lionel does the repair & covers the shipping back to you. Seems like a fair enough deal. Although I will not have my North Pole Central passenger cars for this Christmas season, I am happy that Lionel is doing the right thing by its customers... and I thank them. 
