Signal safari part 3

[NW Mailing List]

The center light in the lower head was known as the “marker” light and was illuminated when the top head of a controlled signal had horizontal lights lit.  The presence of the marker light meant that the signal was a “stop and stay” signal.  If there was no marker light, the horizontal lights on the top head would indicate “stop and proceed at restricted speed”.  To further indicate the “stop and stay”  there was a black metal plate bearing the white letter “S” under the signal number.  This was the “fail safe” in case the marker light was burned out.  In my travels in engine cabs on the old N&W, I never knew of a non-controlled signal that displayed a “stop and stay” indication.

This was the opposite from the Pennsylvania Railroad’s signal rules where the horizontal lights with no marker was the “stop and stay”.  On the PRR, if it had a marker, it indicated “stop and proceed . . .”  If you were stopped at  an interlocking signal on the PRR (like on the Sandusky Line), if the operator wanted to “call you on” through the interlocking, he could cause the marker light to light up, giving you a “stop and proceed”. 

Confused yet?

EdKing



From: NW Mailing List 
Sent: Tuesday, August 06, 2013 12:32 AM
To: NW Mailing List 
Subject: Re: Signal safari part 3

As built, the position light signals had center bulbs in the targets and all the bulbs were amber in color. If any one bulb was burned out, you could still read the position with the remaining two. When they were converted to "color" position lights, the center bulbs had to go, as they couldn't change color when the indication changed. So they still mimicked a semaphore, but with only two lights in a row instead of three. If any one bulb was burned out, you could still see the color of the other one. But the lower target on 408 is something else, as a normal target would not have had a center bulb.

Jim Nichols

From: NW Mailing List <nw-mailing-list at nwhs.org>
To: NW Mailing List <nw-mailing-list at nwhs.org> 
Sent: Monday, August 5, 2013 4:32 PM
Subject: Re: Signal safari part 3


Okay, so can someone explain the differences between 408 & 410?  While the upper targets are the same, the lower ones are not.

Is there significance in that the lower target on 408 has only the center spot lighted?  My very rudimentary understanding of all position lights is that their design was meant to 'mimic' a semaphore, so my expectation here would be that all three lights should be on (and that the illumination of any one of them is the same as if all three were lighted.)

Ed Bell

On 8/5/2013 8:51 AM, NW Mailing List wrote:

  A couple old soldiers at Iaeger, and a shot from Keystone. 
  Jim Cochran


  Moderator:
  http://nwhs.org/wiki/tiki-browse_image.php?imageId=408
  http://nwhs.org/wiki/tiki-browse_image.php?imageId=409
  http://nwhs.org/wiki/tiki-browse_image.php?imageId=410






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