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Re: PC: RI lines, and PC signal question

>> Does anyone know of a source on PC signals? I'd like to scratchbuild a
>> but I don't know the dimensions. I have a few photos, but they're a
>> faded, and I can't make out the details. Any help will be appreciated.

Hard for some to believe, I know, but there are scales other than HO.  Check
for Bob Bartizek's "Pennsylvania and Western,"  an O Scale (3 rail) layout
based on PRR operations around Altoona. He's got a lot of great information
on building layouts, and describes what signals are available in O Scale.
He also gives dimensions.


The standard PRR position light signal target (signal head) was 4 feet 4
inches in diameter with a light in the center and six additional lights
arranged as part of a circle of 18-inch radius. Single signals were mounted
on a mast so that the center of the target was 20 to 24 feet above the
signal foundation. The foundation was set so that the top of the concrete
was even with the top of the rail. For most of their lives, the signals used
all yellow light bulbs. The signal was designed to mimic a semaphore: three
lights in a vertical line meant all clear, three lights on the diagonal
meant proceed but be prepared to stop at the next signal, and three lights
in a horizontal line meant stop.

NJ International, Inc. makes a very nice O-scale brass model of the PRR
position light signal. I say a drawback in the price of these signals. The
single mast signal lists for around $60. Since I needed about 24 for the
railroad, I ruled out this option. I had intended to scratch build the
signal targets out of styrene and use 3mm yellow LEDs (light emitting
diodes) for lights "someday". Then MTH did me a big favor by releasing their

The MTH 7-Light Block Signal is a reasonably good representation of a PRR
single signal mast. The target is about 25% too large in diameter at a scale
5 feet 9 inches with the lights arranged as part of a 24-inch radius circle.
The light hoods are about half as long as they should be, a concession to
the diecast construction. Longer hoods would have been either much too thick
or very prone to breakage. The target is also unprototypically thick, but
this is required to hold the LEDs and the circuit board. The center of the
target is a few inches over 20 feet above the foundation. On my layout, with
Gargraves track on cork roadbed, the top of the foundation is about 4 scale
inches below the top of the rail. The worst thing about the "stock" signals
is the glossy black paint, but I was able to fix that by repainting. The
best thing about the signal (apart from the reliable operation) is that it
is made largely of brass and is put together with small Phillips screws,
which made it easy to modify. Since it uses LEDs for the lights, there is no
worry about bulbs burning out.

MTH's signal has a single smaller light attached to the side of the mast
below the main target. A few prototype signals had this light, so it is
technically correct. It's use was as follows: 1) signal indicating stop and
small light off meant absolute stop, 2) signal indicating stop and small
light on meant stop then proceed at restricted speed, 3) signal indicating
all clear and small light off meant all clear, 4) signal indicating all
clear and small light on meant proceed and be prepared to throw the next
turnout encountered. Most of the PRR single mast signals did not have the
small second light.

In order to make the signal more typical of PRR practice, I chose to remove
the small light, fill the hole where the wires from this light go into the
mast, and repaint the whole thing. In my PRR books, there are photos of
these signals with black masts and others with silver masts. I chose the
silver version. I used Floquil Polly S paints (so I could clean up with
water) in the following colors: Flat Black, Concrete, and Flat Aluminum.
Here is a photo of one of my modified/repainted signals next to a "stock"
MTH one (pic). http://www2.go-concepts.com/~raistlin/prrhpb/pennwest.html

I've also successfully removed the heads from the MTH signals and mounted
them to a Plasticville Signal Bridge. Lucky for me, the Plasticville bridge
is based on a PRR prototype! The signal detection circuits are wired using

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