PSLN 3827 was built for the Southern Pacific Railroad by General Motors' Electro-Motive Division in Erie, Pennsylvania in April 1959. It was part of EMD order number 5595 and was the 43rd out of 45 locomotives included in that order. As such, it was stamped with frame number 5595-43. The locomotive was delivered to Southern Pacific in their attractive "Black Widow" livery and was equipped with gyralights on each end. It was initially numbered 5842. In 1965, in correspondence with that year's system renumbering, it was repainted into the "Bloody Nose" livery and renumbered 3705. During this renumbering, it was also fitted with a 91 Channel Radio. In February 1976, it was rebuilt in SP's Sacramento Shops into a GP9R, and was renumbered 3827. In 1992, its gyralights were removed and it was reassigned permanently to yard service. After the UP-SP merger, it was initially assigned to Denver, before moving to Roseville to supplement the SD7s in 1997. In early 1998, it was given a small paint touch-up by patriotic ex-SP workers and continued to work in yard service at Roseville. On July 3rd, 1998 it was officially retired from active service. It sat in the deadline for nearly a year until it was put up for auction by Union Pacific. On April 15th, 1999 it was sold to the Placerville Sacramento and Lake Natoma Railroad Company, after outbidding the Boise Locomotive Company. Its bill of sale was accepted on the same day it was sold. While it was waiting for transit to PSLN, Roseville-based shop crews took it upon themselves to give the locomotive a touch-up as a show of good faith. In addition to this, its "PSLN" reporting marks were stenciled in white on the long hood, and "FOLSOM" was stenciled on the battery box as that was the waybill interchange location for the PSLN. In addition, it gained a new horn. For its entire career, it had carried a Nathan P3, but it was removed once the locomotive was retired. So, the Roseville shop workers took the horn from another recently retired GP9, specifically 3883, and fitted that horn to 3827. The horn was a Nathan M5, still with its brass color showing. It was delivered to PSLN on May 3rd, 1999, and entered service with PSLN one week later.
Credit to TreeFan101, CodingToTheMaximum, and Western Railroad Videos.