What type of signalling did the Southern Pacific use on the Coast Line? When were the signals semaphore and were these all of the cabinet base type. Did the signals have pointed blades (white/red) or square bladed (yellow/black)? What were the arrangements?
When the signals were converted to lights? What type were employed - I am aware of the different US types such as the oval types with lights in a vertical line of two or three lights [were these called D type as one retailer shows], or round heads with a central, vertical or triangular arrangement [called G type by one retailer], but have no clear pictures of the Coast Line signalling.
I think that I can see single and double round heads in photographs of the remoter parts of the line, with semaphores at LA Union Station.
Quick response: First, try to get Signor’s two volume on the SP Coast Line from Signature Press. The first was publishedin 1994. The second followed by a year or two and was the “pictorial” with mostly photos ands some additional text. Second, there was a book on Signalling published in the past several years (MBI or Boston Mills…??) that is the best explanation of the home and distant signals I’ve seen. There are several websites on RR signalling that shed light as well. Third, at great risk, here’s a thumbnail overview of Coast Line signals: 1. Eaarly, ninteenth century signals at both SF and LA ends of the line. 2. Coast Line completion, December 30, 1900, nearly coincides with E.H.Harriman control of SP. Harriman was a BIG advocate of improved safety. Union Switch and Signal, Style B semaphores (both single blade and home-and-distant two blade masts) became a symbol of the SP. 3. US&S Type SA searchlitghts began replacing semaphores in the 1920’s. Semaphores and Serchlights co-existed for a very loing time. They nearly define the lineside look of the SP in the 20th Century. Reasons for replacing semaphores could be line changes, basic maintenance headaches, or installation of Centrallized Traffic Control (CTC). 4. Triple light signals began invading around the 1980’s, though this is a very lose timing. Various styles are in use today, including the old US&S SA searchlights. Both the semaphores and SA serchlights used relays. That’s wha is in the cases at the base of the mast, or sometimes in a separate case mouting off to the side. The modern signals use solid state circuits, usually in a separate control cabinet near the signal installation. Maintenance is what leads to the replacement of the relay-controlled signals. This replacement is on-going. One more symbol of the SP vanishing…
Addenda to my earlier post. The “Railroad Signalling” book by Brian Solomon, MBI, 2003, is one of the best overviews of signalling I’ve seen. As noted, it will help you understand the indications of the second blade (or signal) on a two-headed mast. There are other variations, involving “lunar” signals as well, but the sense of the original question concerns the basic signal aspects.
Just considering the single-track ABS parts of the line, in semaphore days most signals were single-red-square-tip-blade, two-aspect. I assume the usual practice was to make the eastward signal at the west end of each siding a two-blade, along with the next eastward signal west of there-- and correspondingly with signals in the other direction. But I never have studied pics to try to see if this was really true.
In Beebe’s “The Trains We Rode”, the pic at the beginning of the SP section shows some unknown westward train at the east switch of Grover siding; in that case, I assume the eastward two-blade signal is the approach signal for the west end of Oceano siding, not far to the east.