Don't know how to read semaphore signals

I don't know how to read railroad semaphore signals and was hoping that someone might be able to tell me, possibly with visuals, or direct me to a relevant website or other resource.

I have been running some searches, but most come up with ways to buy model signals or pictures of signals. My problem is that considering featuring some on a layout yet I want to be reasonably prototypically accurate. For this, I probably ought to know how to read them and where they would be placed and why.

If it makes any difference as to railroad, I am primarily interested in how Southern Pacific would have used them, and, if applicable, BN/GN/SP&S.

Thanks in advance,
Adam

 

Adam, have a look HERE. This has a good description of both upper and lower quadrant sempaphore signals and their indications.
One shows a lower quadrant pointing down 90 degrees for a clear indication, something I haven't seen before. All of our's are two-position - horizontal = danger/stop, 45 deg down = clear (for non-distant signals).

SP ABS signalling with both semaphore and colour light application diagrams - Railroad Signalling: SP DTC/ABS

 

Gary,

Thanks for the link. I kept finding stuff that was close but which lacked any actual explanation. I was about ready to call up my ex-rail (and nearly 93 year old) grandfather and ask him, since he spent all those years as a conductor on the UP. I think I will just wait until I see him on Sunday (his birthday) since he has a heck of a time hearing on the phone anymore since I think his communication is reliant on a little lip-reading and looking at people's gestures.

For a while, CORP was selling off removed SP signals. You needed to be present at their removal with your own crew and with some way of loading a 1200-1300 lb. signal onto some sort of truck, also provided by you. I think they were charging $1500-1800 per signal. I don't believe they are still doing this, but I found some scale drawings of a semaphore signal here and it has my mind running about how I might be able to fabricate, say, a scale replica in my backyard. I probably wouldn't go the full height simply because I don't have the kind of acreage that would really make it stand out.

Adam

 

The mechanism is the part I am having the most difficult time figuring out.

 

What about the mechanism are you having difficulty with?

 

Semaphores have 3 positions, vertical, horizontal and at a 45 degr angle. It can be up or down. Either way it means the same thing. 45 degr up means the same as 45 degr down. Vertical up means the same as vertical down.

Horizontal = red
45 degr = yellow
Vertical = green

With that decode you can change virtually any color light signal into a semaphore.

The best bet is to cruise E-Bay for rule books (or rulebooks) for the railroads or era you are interested in. They will show all the signal indications used. The risk is that the SP occaisionally used unique indications that weren't exactly industry standard or had rules that were unique to the SP.

Dave H.

 

The problem I am having is figuring out how to fabricate a mechanism at, say, 3/4 or 1/2 scale. Of course, I could just have it hand controlled with some sort of rod instead of trying to make it servo-controlled.

Adam

 

Thanks for the quick run-down, Dave. I think one of the guys in my club has an SP rulebook, and I know another guy has an SP&S rulebook.

Adam

 

Why not try for a 1:1 scale working electrical upper quadrant signal? It doesn't need to be on a full height post and you already have the 12VDC (maybe 110VDC or AC?) mechanism included. The rotary contact arrangement within will give you the position depending on input.
Otherwise, using a mechanical rod/wire drive would be better suited to a lower quandrant signal, which is the way they work.

Remember, even at 1/2 or 3/4 scale there is a lot of weight involved and the control mechanism will need to be made to deal with it, notwithstanding the machining/fabrication required to produce a scale signal in the first place.

 

I guess maybe I should see if I can find one. I found a blade on eBay but it doesn't include much. I could fabricate a reasonable facsimile of a blade. It's the spectacles and mechanism I would most love to locate. I am hoping I will come across one somewhere for not much money that needs some work, since I like staying married more than the $1500-1800 it would cost to purchase a full size on in working order.

Adam