|It's been a long time since I'd gotten to see an ex-MP Non-Dynamic Brake Equipped SD40-2 leading a train. I finally got to see one again today. UP 7878 was built as MP 3309 in December 1979 with a Builder's Number of 796308-8. This combination of motive power made one heck of a racket. This unit was actually retired in 2001, and then reactivated in 2003.