CPL signal aspects

[NW Mailing List]

The westward signal at Pearisburg is capable of displaying Diverging
Approach Diverging.  That's at MP N-329.9.  Flashing is controlled by a WC
705 solid state flasher.  I assume this is a Western Cullen model.  The only
thing I found in their on-line catalog is the Model 730.  You can look it up
yourself, but the flash rate is 45 to 65.  I will assume the rate is 45
(standard for train signals) and 50-50 on-off operation on the 705.    FRA
will allow this variance in highway crossing signals, but I don't believe
they have a position on train signal aspect flash rates.  I could be wrong
as they issue "interpretations".  I would go with a 45 rate if I were
designing something to mock the train signal.  As for seeing the signal in
operation, it would be a lucky person indeed to wander up on that aspect in
operation.  If it were me I would seek out the signal maintainer and buy him
a lunch!
If you are interested in seeing the print for this location, e-mail me
off-list at NW2012Y3 at bellsouth.net, OK?

John Marbury
Buford, GA



In the case of a CPL signal aspect in which one of the "arms" is flashing
(as in "Diverging Approach Diverging": red over flashing 45 degrees), what
is the rate at which the lights flash?  That is, how much time elapses from
the time when the lights just start to burn on one cycle, until they just
come on again for the next cycle?  I'm guessing its a couple seconds, but
never having seen this indication, I want to get the facts straight.  Also,
what is the "duty cycle" for this type of flashing, i.e. how long are the
lights on during a cycle compared to how long they are off during the cycle?
First assumption would be that they are on exactly the same amount of time
that they are off and therefore 1/2 of the cycle time, but again I'm hoping
that someone out there has the real data.  And by the by, where would be a
good place to observe a CPL signal displaying this aspect?  I am trying to
get photos of CPL signals (while they last) displaying all the aspects, but
for this one
  it will have to be video.
Thanks,


Jim Cochran

dcochran116 at roadrunner.com

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