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Re: (erielack) DL&W single-light signal heads



Please see :http://www.railroadsignals.us/rulebooks/dlw25/index.htm
Many DLW signals would only have one lighted signal on the bottom of the 
two heads, as in the clear signal where only the green was lit and the 
only green was in the bottom head.
Approach Medium means approach NEXT signal at not exceeding medium 
speed.  The engineer would know how far in advance the next signal was 
and reduce his speed accordingly. However the DLW in 1925 did not have 
an "Approach Medium" aspect;  Yellow over green was "Approach 
Restricting"  meaning approach next signal at Restricted Speed.  The DLW 
also did not have a "Medium Clear" as such. Medium Clear would normally 
be at an interlocking and indicate medium speed through the interlocking 
switches [with the entire train] and then normal speed [clear] to the 
next signal.

On 7/21/2011 6:16 PM, Don Liotta wrote:
> Does Medium Clear mean proceed at half the speed limit? And does Approach
> Medium mean proceed to the next signal at half the speed limit? I don't
> fully understand the terminology used in reading signals.
>
> Don Liotta
>
> -----Original Message-----
> From: Wdburt1_@_aol.com [mailto:Wdburt1@aol.com]
> Sent: Thursday, July 21, 2011 5:38 PM
> To: erielack_@_lists.railfan.net
> Subject: (erielack) DL&W single-light signal heads
>
>
> A single light, same size as all the others, in a round  target.  US&S
> called them an HC-33 marker light, IIRC.
>
> Erie used them in a variety of applications, most commonly on  three-headed
> interlocking home signals that displayed only aspects where the  bottom or
> top signal head was always red.  Take a look at photos of Marion  or other
> complicated places and you'll see a few of those.
>
> Erie never (so far as I know) accepted the idea of using a dark signal head
>   as part of a signal aspect.  A dark light was to be interpreted in the
> most  restrictive manner possible.  The DL&W did allow it, and made
> extensive
> use of darkened signal heads to convey various aspects.  For instance, some
>
> signals on the Scranton and Buffalo Divisions were set up with the marker
> light  below a standard, three-light color light signal head.  The upper
> head
>   could display red, yellow, and green.  If the upper head displayed yellow
> and the marker light came on displaying green, that changed the indication
> from  Approach to Approach Medium.  As you DL&W guys probably know, the
> railroad also made extensive use of two-over-two configured signals where
> the
> green light was on the bottom.  Some of these were used at  interlockings.
> In that application the only thing needed to convey Stop  was a red light
> burning in the upper signal head.  Add a green light below  it, and you got
> Medium Clear.  This configuration was also used in some  wayside signals to
> provide Approach Medium as discussed above.  In that  case one of the two
> lights in the lower target usually would be blanked  out.
>
>
>
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