My understanding of Caliphonia's Franchise Tax Board is that they can charge a sales tax on ANY new equipment that is operated in the state for more than 48 continuous hours within the first 90 days of being built, regardless of where it is built or bought. I recall Espee sending many of their new diesels, including the GP-40P-2 commute engines, to Oregon to dodge the tax.
When I first hired on with Conway, I spent several evenings pulling brand new sets of doubles from the Road Systems plant in Fontana to the CWX yard in Santa Fe Springs, where they were immediately loaded for Phoenix and Las Vegas. Inside the trailers were stickers warning " Do not load this equipment to any California point until ( a date that was at least 90 days later was written in here )".
Joe Strapac has explained in his Southern Pacific Historic Diesels series that the St. Louis - Southwestern RR, having gone through a bankruptcy & reorganization during the depression, had little debt and therefore a better credit rating than parent Espee did.