|What a treat! This is a former Mo-Pac SD40-2c, the "c" for coal. A few were built to BN specificatations for MP/UP/BN/D&RGW coal power pool. These were ballasted to up to 417,000 pounds for more tractive effort, had dynamic brakes, and were equipped with a MARS Light like Rio Grande units, and a rotating beacon like BN units. Otherwise they were MP features. It was built as 3219 before more coal service units were built. They were then renumbered into the 6000 series and more non-dynamic brake equipped units were built in the 3200 series. More photos of it as UP: http://www.trainweb.org/screamingeagle/other/j_glenewinkel/UP3903/UP3903.jpg , and as early GATX: http://www.rrpicturearchives.net/showPicture.aspx?id=16920 . Notice it lost its MARS Light when it was painted blue. More info on the SD40-2c's can be found at: http://www.trainweb.org/screamingeagle/loco_2gen_sd40-2c.html .