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Sat Sep 29 23:43:15 EDT 2012
The spredlight lens is what we call a barbed wire lens. Most of the PL signals had regular red and green lenses like the yellow one in your first photo. The barbwire lenses were used on the serpentine portions of the railroad. They are to help spread the light beam more in the horizontal range. They do shorten the range a little but the gain in the side view makes up for that.
I haven't heard why the voltage change was made but it could have been the adding of color.
As to the change to CPL from PL, I was told by a now retired signal supervisor who was a signalman in the day that the change came after the PRR gave up its hold on the N&W (around 1958) and company management wanted to make it clear they weren't part of the Pennsy anymore. The signals received the silver paint at about the same time. This attitude surfaced later when the N&W acquired the Sandusky line from PRR. They had MOW cut the tops off the keystone whistle boards because 'This isn't the Pennsylvania RR anymore'.
Lead Signalman Gang 677
N&W Ry (or NS as THEY call it)
> My question is: Was it really necessary to change the pattern of the prisms on the lenses when adding color to the standard PL signals, or was this just a matter of a salesman generating some extra commissions?
> I also wonder how these 25? Spredlight lenses affected the range of a signal.
> As a matter of speculation on my part, the application of the "denser" colored red and green lenses (i.e. less "transmissibility" than yellow) might have been the occasion for the N&W jacking up its signal lamps from the older 9 volts 12 watts to the newer standard of 10 volt 18 watts. Denser lens? Just force more light through it !
> The ostensible reason for the addition of color to the N&W Position Lights Signals was a side collision between northward passenger Train No. 2 and a southward freight train at the south end of Cloverdale Siding.
> As for the 25? of "spredlighting," perhaps someone thought this would be advantageous on some of the N&W's rather serpentine trackage. But who knows, since there don't seem to be any records???
> -- abram burnett
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