I lived in Cuzco, Peru in 1965 and part of 1966 and frequently visited the San Pedro station to enjoy the daily display of steam engines of the Ferrocarril Cuzco-Santa Ana. At that time ex-SV #50 was in the main shop building undergoing a major overhaul and was not readily accessible. One day I found the brass front number plate of the locomotive buried in the dirt floor of the roundhouse and placed it on a shelf as I appreciated the privilege of ready access to the station and roundhouse.
I was told that the locomotive was being prepared for service on the extension of the railroad from Chaullay to the city of Quillabamba. There is an excellent photo of #100 (ex-SV #50) on the Cuzco turntable by J. Stebbins on page 75 of Railways of Peru - Volume 2 - the Central and Southern Lines by Robert D. Whetham published by Trackside Publications.
At that time the railroad also had several handsome American 2-8-2s in regular service - Baldwin #123 (named Ingeniero Vinas) and Alco #128 (ex-Lima-Lurin Railroad). At that time there were several other Baldwin 2-8-2s similar to #123 that were stored out of service near the San Pedro station.
I have noted that the ex-SV 4-6-0 was still listed on the railroad's locomotive roster in 1977.