After the rebuilds, these locomotives were used through World War II. The first to be retired from active service were numbers 4040 and 4045, both on October 21, 1946; the last to be retired was number 4032 on August 8, 1949. All of this class were scrapped soon after retirement.
References
Diebert, Timothy S. and Strapac, Joseph A. (1987). Southern Pacific Company Steam Locomotive Conpendium. Shade Tree Books. ISBN0-930742-12-5.{{cite book}}: CS1 maint: multiple names: authors list (link)