Common standards for SP Depots

From: "Barbara Toppings" bdtopping@roadrunner.com

Where can I find information about the "common standards" for SP Depots? I've roamed through the entire Q & A section without seeing a single word on this. I'm looking for who designed the plans, and which plans were used for each station, and how they were assembled on site. A local newspaper (Ventura, CA) in 1887 when the train tracks arrived in town says they were prefabricated in the Sacramento shops, but there isn't a hint in the CPRR page on that topic.