N&W's Use of PL-2 Position Light Signal Equipment

[NW Mailing List]

The Long Island Rail Road also used US&S position lights.  Of  course, it 
installed them while under Pennsy ownership.
 
Dave Phelps
 
 
In a message dated 4/23/2012 6:49:26 A.M. Eastern Daylight Time,  
nw-mailing-list at nwhs.org writes:

 
There were only two major customers for Union Switch & Signal Company's  
Position Light Signals, the N&W and the PRR.   
There were three different generations of PL signal equipment: the original 
 PL-1 equipment which came out in the early 1920s, the PL-2 version dating 
from  the 1930s, and the PL-3 equipment of the 1940s and 1950s.  The 
difference  in the three generations of equipment was the optical systems employed 
in  the individual lamp housings... all the signal mounting  hardware 
remained the same through all three generations of  equipment. 
The N&W was buying PL-1 equipment in the 1920s, by the 1940s had  switched 
to the PL-2, and never appears to have used the PL-3.  The PRR,  on the 
other hand, widely installed the PL-1, then switched directly to the  PL-3 and 
never appears to have utilized the PL-2.  I always wondered why  the N&W 
never upgraded to the latest PL-3 refinement, and why the PRR  never used the 
PL-2. 
Recently I completed restoration of one each of the PL-1, PL-2 and PL-3  
lamp housings, and mounted them vertically for display, and I think  the 
reason the N&W never bought PL-3 equipment has  become apparent. 
Using 9 volt 12 watt signal precision lamps in each, with all housings  
equipped with standard amber "NoViol" ("no violet") glass, and all  juiced at 
5.6 volts, there are easily observed differences in the  light-emitting 
properties of the threee generations of equipment. 
1.  The PL-1 lamps system gives what was probably a respectable  light in 
the early 1920s - it certainly was better than the light provided by  a 
semaphore signal. 
2.  The PL-2 equipment (which was N&W's second-generation of  Position 
Light Signal equipment,) with its revised optical system, gives a  brilliant 
light, significantly better than the old PL-1, and the lens was  engineered 
with  a horizontal band of ribbing across the middle  portion of the inside of 
the lens to provide a wide "spread" of light  from side to side.
3.  The PL-3 equipment (which appears to have been bought by only the  
PRR,) has an optical system which gives an ENORMOUSLY brilliant  light, a light 
which indeed "burns the eyeballs," even when the  lamps are burned at 40% 
below rated voltage.  However, the  pencil-beam of light is significantly 
concentrated and there is no attept to  "spread" it from side to side. 
Now granted these are close-up observations and do not replicate the  
2,500-3,000 range expected from a working signal in the field, but I think  they 
answer the question why the N&W never bought the latest version of PL  
signal equipment.  The PL-2, with its "spread," was the perfect signal  for a 
railroad with significant curvature problems, and the PL-3 equipment was  the 
perfect signal for the PRR. 
During my restorations, I photographed the optics and dead-on front  views 
of each version of the PL equipment while illuminated during  darkness, and 
as soon as I go through all the historical and technical  material again, 
will assemble the data, the photographs and the conclusions  into a PDF, and 
offer it to anyone who cares to read it. 
One final test remains.  The next time Mrs. Boss goes away for a few  days, 
I shall rent a "fog machine," fill the basement up with fog, and observe  
the relative "fog penetrating" characteristics of the PL-2 vs. PL-3 equipment 
 ! 
Do the N&WHS Archives contain any material relating to tests and/or  
purchases of  PL-2 signal material? 
-- abram burnett
///////////////////////////////////////////////////////////////////////
The  wise philosopher Theocritus was asked which
animals of the forest are most  to be feared.
Theocritus responded:  "While in the hills are  lions
and bears, yet in the city are tax collectors and
lawyers and  sycophants, and the latter are much more
dangerous than the former.  The beasts are
irrational.  Man calculates his  wrongs."
///////////////////////////////////////////////////////////////////////





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