old semaphore dimensions?

[gregc]

can anyone provide dimensions for the semaphore in the picture: height of the pole, pole thickness, semaphore arm length, arm width?   thanks

 

[ACY Tom]

This seems to be a hard one to figure.  At first, I was going to suggest that the person might be a child; but on closer examination, I'm guessing it's an adult, but possibly a verry short adult.  So I think it may be deceptive to use that person's size as any kind of a gauge.  The door height is also deceptive because it probably has a transom at the top, and who knows what might be the actual height of the door itself? 

I suggest that the best reference may be the telephone pole, which probably has a diameter around 10".  (I determined that by going outside and checking the circumference of a nearby small telephone pole, which was 29".  29" divided by 3.1428 = 9.227").  The pole for the signal seems to be about the same size.  I think I would use the pole as my standard, and derive the other dimensions from that.

If you can identify the actual location, maybe there is a record of the station's dimensions, or some record of common standards for stations of that particular railroad (Philadelphia & Reading?).   Those bits of info could be helpful.

Have you checked with the RDG Tech. Society?  They may even have drawings of that signal type.

Tom

[7j43k]

Tom answered beautifully.

 

Nevertheless, I'll make an addition.

 

I ASSUMED the rise for the 3 steps behind the man was 8".  From that, I get the man's height to be 5'-7"--a not uncommon height for the times.  Sadly, there's a bit of variability in step rise.

 

But, still.......

 

 

 

Ed

[ACY Tom]

Excellent point.  My dad worked as a carpenter at times in the 1940's and early 1950's.  I seem to recall that he told me the ideal dimensions for steps involved a 9" tread, and an 8" rise, for a total of 17".  He said you could vary the tread and rise dimensions, but the total should equal 17".  That was considered a pretty good match for the normal stride of a typical person on stairs. 

Tom

[gmpullman]

Hi, Greg

Maybe this will be of some help? My grandfather, Frances X. at the B&M depot in Barre Plains, Mass. taken in 1917.

I have the porcelain sign and it measures 12" top-to-bottom. You can see the train order semaphore in front of the bay window and, to me, it looks like it is 10" square. I wonder if you can find out what depot is shown in your post card and find plans for it or similar plans from that railroad? It would give you the height of the peak. Most often, visibility dictated the height of signals so you could make allowances on your railroad to suit.

This is a pretty low resolution scan I did a few years ago. When I find the photo again maybe I can do a higher res. scan for you.

I googled Images>railroad semaphore signal drawings and quite a few old patent drawings came up but none with any real dimentions of any help.

Good luck, Ed

[dknelson]

That is such an interesting photo because it shows two types of blades -- the upper is square/flat ended and the bottom set is fish tailed.  Ordinarily that means one is for train orders and the other is for blocks but railroads rarely liked to put both types together at a station.  Perhaps one is for an interlocking?  Those were generally square ended.

It is my impression from older photos that semaphore blades got shorter over time -- the "modern" blade was usually 3'6" and the tip of the blade was anywhere from 3'10" to 4' 81/2" from the pivot point of the semaphore itself.  I got that 4'8 1/2" length from a drawing in the 1944 Model Railroader Cyclopedia.  None of its drawings were specific to that era or railroad.  These look longer to me than the "modern" blades.

Dave Nelson

[steemtrayn]

Too bad the track at the same distance as the signal is out of the picture. Otherwise, you could just compare it to the guage.

[mlehman]

Dave,

Yeah, I remember seeing shorter blades somewhere, but I suspect that may be specific to a RR or maybe regional use. I remember the Monon ones, as well as others. It being track gauge sounds about right, but I bet this had more to do with visibility than anything. A smaller balde is less visible.

4' 8.5" also sounds about right for the ones I've seen up close. Max blade width 10", maybe a little more?

[gregc]

based on estimates for the telephone width (10") and step height (8") i get

• arm lenght from 5' to 6.7'
• arm width from 8.2 - 11"
• pole height from 24 - 32'

i think the lower measurements are more likely