Garrie Tufford called me this morning to discuss this thread and also to point out that I might have the answer to what came to be SVRy caboose 4 at my fingertips. This by way of the SVRy journal of "Freight and Express Bills" which our archives holds covering 1902-1913. I took a look at the entries for 1903 which shows the arrival of the cars from OSL, listing the car number they arrived on and in most cases the OSL narrow gauge car number and type of car. On May 20th 1903 among the many cars that arrived in South Baker was caboose # 025772. On June 12 another batch of cars arrived which included a number of cars noted as Exn. cars most with numbers listed. I assume Exn. stands for excursion. There is one arrival noted as "Caboose-Exn" with no number noted. Also on June 12th is a 3rd "Cab", but again no number shown. The car numbers that the narrow gauge cars arrived on is listed so are there any records extant from the OSL end that would show what narrow gauge car number was shipped on what standard gauge car? Sadly no confirmation as what became SVRy Caboose 4 yet.