https://goo.gl/maps/Hvdok6admkGeDKzBA
What kind of signal is that red x on the two section for?
If I had to ask, maybe a MUNI (bus) queue jump to go straight (or even left)?
I’m not from there. In Florida we use white PRR positional signals in a three section head for buses.
See below.
Upgrading the T: Weigh in on a New Type of Train Signal on 3rd Street
Rachel Hyden, 22–FEB-2017
Implementing a Standard, Concise Design for Train Signals
Currently, Muni trains are guided by three different types of train signals. We’re in the process of upgrading 400 signals along the T Line to one uniform system within the next few months.
The three designs used for existing train signals (left) which will be consolidated into one standard type of signal (right).
Oh, that's interesting. I like this concept, but the red "lowered semaphore" is specifically not recommended by MUTCD because the red lens can be illuminated by sunshine and therefore be misinterpreted by automotive traffic. That being said, I'm pretty sure that it is not specifically discouraged because a misinterpreted red traffic signal is not inherently unsafe (even though there are some safety issues related to the next car seeing a green signal). I doubt that there are any situations where a red (or lunar white) "lowered semaphore" transit signal is displayed for a route where automotive traffic is given a green phase.
Fun fact: What Roadman65 affectionately calls "PRR positional signals" is an attempt by certain railroads to duplicate the position of a magnetically-activated semaphore blade with an attached multiple-lens searchlight signal head. The Baltimore and Ohio had color position light (CPL) signals and the Pennsylvania Railroad (along with the Norfolk and Western and others) had position light signals. The top-and-bottom positions are for a clear aspect (no obstruction ahead in the next two blocks, a situation where the semaphore blade is standing straight up (to simulate a signalman with a lantern held up). The 45-degree diagonal positions are for an approach aspect (approach next signal prepared to stop). The left-and-right positions are for a stop aspect, a situation where the semaphore blade has a lowered arm (to simulate a signalman with a lantern held out). The B&O had green-yellow-red lenses in these positions, respectively; whereas the PRR simply used lunar white lenses all the way around.
By the way, there is another position (the minus-45-degree semaphore blade) which is a "call-on signal" where the dispatcher has specifically granted the train permission to pass a stop signal. Those are always lunar white, no matter which railroad and what type of signal. (Don't get this confused with what other railroads used as lower-quadrant semaphores).
