On pages 356 and 359 of the book Southern Pacific Daylight Locomotives, It shows a photos of the Texas and New Orleans 4-8-4s built in 1930 of the 700-703 series that has tenders equipped with a brakeman doghouse mounted on the top of the tenders for the brakeman to sit in required by Texas state law. When the locomotives reached california the doghouses were removed from the tenders.The book doesn't tell why but can you tell me why the doghouse were removed in CA and why CA doesn't allow brakeman doghouses on steam locomotive tendres.
It's unlikely California didn't allow them, more likely they didn't require them like apparently Texas did. If SP only added the doghouses to engines in Texas because Texas law required it, they might well remove them when the engine was transferred to work in a different state.
I hadn't heard about this being required before, I wonder if TX was the only state that did this?? Searching online through your state's (or the states you model's) statutes can turn up some interesting things. Here in Minnesota, cabooses have been required to have at least two four-wheel trucks and be at least 24' long since 1911, so no bobbers allowed here!! Same legislation banned any gauge except standard gauge for common carrier use - but the last Milwaukee narrow-gauge line had been converted to std gauge in 1903 so it didn't really change anything.