Nostalgia & History > semaphore colors

Here is another in my series of questions which apparently no one can answer:When did the Southern Pacific change the color of their type B semaphore block signal instrument cases,masts,finials,etc.from black and white,to silver or aluminum.Thanks.

The earliest photos of silver-painted signals on the SP that I've seen were taken in 1932 and 1933.

Page 74 of Signor's "Southern Pacific's Coast Line" had a photo supposedly made in 1932 that shows a silver signal on Cuesta grade (middle photo).

In the Otto Perry Collection at the Denver Public Library there is a photo taken in 1933 that includes a silver signal (the ID number for the photo is OP-16081). Probably the best way to see Perry's SP photos after going to library's website is to find the page labeled "DLP Western History Photos" and then type in the search box "Perry, Otto, Southern Pacific".

In the 1934 movie, "Murder in the Private Car,"
all the SP signals seen are still in the old paint scheme of black and white. This movie was made in and around Dunsmuir and was most likely shot the previous year, 1933.