P&D F unit kits


A&O Historical Society
The O-scale forum seems way too quiet, so here goes...

If you model 2-rail, take a look at the F unit kits that P&D Hobby Shop has on fire sale. They are great kits (I've built 3 and have 4 more to go) and they provided me a much-needed reintroduction to the hobby after 30 years of absence.


Photo taken on David Stewart's Appalachian & Ohio

I opted to get the single tower drives (still all wheels powered) to leave room for an optional detailed cab kit. These locomotives sport fully-sprung and highly-detailed lost wax brass trucks that Atlas apparently did not want when P&D sold the tooling.

With DCC control and an NCE 408 decoder, there are lots of function outputs for special effects, such as overhead cab reading lights.


Submitted for your approval. Frank and Jim's F3 just exited the tunnel that they run through every day without incident. But today is different. Today they came out into a place that is dark and devoid of scenery. Turning on overhead lights, they frantically search the employee timetable to see where they are. But this station is not in their employee timetable. They just arrived at... the Test Track Zone. (cue sound do-de-do-do...)

A chip LED will just fit inside the hollow back of the lost wax speed recorder, which is part of the optional cab kit.


Chip LED installed in the speed recorder and backfilled with ACC.

There is plenty of room to add gage lighting. Opening up holes in the etched "dashboard" is quick and easy by applying a sanding drum in a Dremel to the back of the part. During assembly, a thin sheet of frosted plastic film acts as a diffuser. This too is part of the optional cab kit, and it only fits if you get a single instead of double tower drive.


Opening up the "dashboard" for lighting.

Here is a peek at the completed cab.


If there is interest, I can post more construction details, although probably will be a few weeks before I'll have time to respond.

Yes? No? Maybe? Your call.
Great work on the layout, and the engines. I'm looking forward to the new A&O. While I haven't done anything with the P&D F units, they sure do raise the bar for reasonable price and fantastic looks. Did you make the f units all wheel pick-up for the power?

Greg Elems
Yes, all-wheel pickup is a big help.


The pickups are thin phosphor bronze, formed with pliers, applied to the back of every wheel. Both P&D and NWSL replacement wheels arrive with a dark, greasy coating that must be removed for good contact. I did this by wet sanding with 400 grit carbide paper and a light oil (water would make the wheels rust.)

The pickups are held in place using the screws that hold the gearbox halves together. The "stiffness" of each pair can be adjusted with needlenose pliers to minimize end thrust on the axle.

I do find that these steel or iron wheels seem to get dirty a lot faster than chrome(?) plated brass used by Overland and other importers.

As for sander hoses, I used 1/16 diameter black heat shrink tubing instead of the material provided in the kit. Before installation, shrink the tubing with heat. While it is still warm, it can be bent into a curve that it retains when cold. Gently expand the end with an awl to enlarge it enough to slip onto the sander.
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Here is one way to illuminate the number boards.


With a little filing, a short piece of Evergreen rectangular styrene tubing will just fit inside the brass P&D number board castings. This replaces the kit's white plastic insert.

A color-corrected white LED (illuminated in this photo) shines on the back surface of the tube, so that light is evenly diffused by the time it gets to the front surface.

The round tube houses a red LED to illuminate the class light. The black paint keeps red light from showing up in the number board.

I chose to power the numberboards with DCC track power, so they are always on. To do this, connect the LEDs in parallel, but back-to-back. Then run them to track power through the dropping resistor of your choice (a 2.2K, 1/4 watt resistor would work well.)

Why back-to-back? DCC power is AC, meaning the polarity constantly swaps. At 14.5 volts, it exceeds the reverse voltage rating of any LED with which I'm familiar, and would be sufficient to eventually damage an LED. By connecting them back-to-back (i.e., anode of each connects to the cathode of the other), one LED will always be on, regardless of DCC polarity. And when one diode is on, it automatically limits the voltage across the other one to a safe value.

Then there is the question of how to make number boards that can be back-lit. The A&O primarily uses white numbers against a black background. For this I used an ALPS printer to print the black background on overhead transparency film. I flopped the numbers left-right so that the printed side would go next to the lighting unit. A light airbrush coat of PollyS "dust" gave the white numbers a translucent, frosted appearance.

Here's the finished effect.


The red class light, when powered by a function output of an NCE 408 decoder, ended up way too bright, perhaps because is a clear high-efficiency red LED. Someday I may increase the resistor value to 10K - 20K to make it appear more prototypical under normal layout lighting.

One more thing - check out the lost-wax grab irons. These are from optional P&D kits and IMHO are definitely worth the extra expense. Installation does require a bit of skill with a #17 blade to carve off a few cast-on NBW details from the body.

Note: please know that all photos are copyrighted and these or similar ones may be submitted for magazine publication at a later date. But my friends you saw it here first!
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Sweet, One reason I wouldn't mind to play with O or G scale, awsome detail! I might just have to build a "mini" G scale layout to play with too...
Chris -

Yes, David's A&O was featured in the May 2006 issue of Model Railroader. The locomotive described in this thread was the lead unit on the magazine cover.
ncmrdispatcher said:
Chris -

Yes, David's A&O was featured in the May 2006 issue of Model Railroader. The locomotive described in this thread was the lead unit on the magazine cover.
Thanks for clearing that up. Tell him that I enjoyed looking at his work, it was truly magnificent!