Guns,
As I indicated before I do believe they are faulty LED's supplied to Lionel, from the over seas vendor. I saw this happen to one of my friends who was building a different product, it is almost impossible to stop QC wise unless they inspect ever single item sold. Similar to when we were kids when the they shorted a few nuts and bolts on every item sold, to make millions, same game different product line.
PCRR/Dave