P&D F Units


Last February I got a Red Caboose GP9 from eBay and the instructions were missing (as well as a few parts). Bob was kind enough to send me a scanned copy of the instructions. I would like to return the favor by sharing some of my work. The GP9 is on hold while I am working on an ABBA set of P&D F units. One AB pair are F9’s and the other two units are late model F3’s. They will be for my freelance railroad, but detailed according to Southern Pacific practices

The F9‘s will have 1500 gallon fuel tanks. The 3mm wide piece down the middle is to widen the original tanks because they are too narrow for the space between the side skirts. I had to do something similar with the battery boxes. The lower curves of the tanks were made with PVC pipe cut into quarters. The tanks will be filled with BB’s to help add weight.

This is the fuel tank with about half of detailing complete and mounted on the F9 B unit.

This is the F9 A unit. The piping on the roof sticks up a little at the rear because it is not glued down yet. This won’t happen until after the unit is painted.

It seems I can only post three pictures at a time, so I will continue in another message.



The A units will have ice breakers on the roof. These breakers haven’t had the bolts or mounting pads added yet.

Many railroads had an extra seat in the cab for the head end brakeman. The switch box on the control stand wasn’t quite right (for SP, anyway) so I decided to rebuild it.

All four units are powered and all had loose drive chains, so I added ball bearings to tighten the chain by pushing it aside a little. This idea came from an article in O Scale Trains Magazine.

Hope you all had a good Christmas. I’ll post more pictures later, if you like.



Beautiful work there, Robin! By all means, please post more photos.

What are you modeling on the end of the fuel tank? Is that an oil recovery tank of some kind? I’ve seen some tanks on Rio Grande Gp40-2s, but 5771 at the Colorado RR Museum doesn’t have anything like that. I’m not familiar with SP customization. I’m also guessing that this engine is freight only so it doesn’t have the split fuel/water tanks to support a steam generator.

By the way, do you have a good drawing of the brake air cooling coils on the roof? What did you use for the pipe fittings?


Very nice Robin. Excellent work. Can’t wait to see the next round of photos!


Thanks for your comments. I wanted to upload two more photos, but I get a “Sorry, the board attachment quota has been reached.” message. How do I get around this? Do I need to start another Post?



Robin -

Your suspicion is correct. Any single post can have at most 3 photos. Just reply to yourself and add more photos. We won’t think that you are talking to yourself (though some folks wonder about me…) :laughing:

Bring on the photos! We would love to see more of your work.


[quote=“Bob”]Robin -

Your suspicion is correct. Any single post can have at most 3 photos. Just reply to yourself and add more photos. We won’t think that you are talking to yourself (though some folks wonder about me…) :laughing:

Bring on the photos! We would love to see more of your work.[/quote]


That’s what I did (replied to myself). I clicked “Browse” to upload a picture, then I clicked “Add the file”. The window with the progress bar appeared as if the picture was uploading. When it was done, the message appeared, but not the picture. Just in case, I tried this with different photos with the same result.



I shot an email to the webmaster asking about this problem. Googling the error suggests that there is a limit to the total number of attachments that can be uploaded to the forums, and we just hit that limit. Either that, or some maintenance that the webmaster did earlier this week had an unintended side effect.



I quickly discovered the size limitation but that was easily fixed by using a little compression on the pictures. I haven’t heard anything from the webmaster and I still can’t upload anymore pictures. I wanted to answer your previous questions with a couple of pictures. Maybe for now I should just start a new thread??




I discovered by accident that I can now add more pictures. To answer your questions:

The 2mm square strips on the bottom of the end of the tank is the fuel tank sump. The NBW castings represent plugs that can be removed to drain the tank. The box with the cut corner is the emergency fuel cutoff. The knob on the side is the reset knob. On the standard 1200 gallon tank these items are mounted on the bottom of the tank. On the 1500 gallon tank they are mounted on the end for clearance reasons. There are still some details I need to add to the end.

These units are for passenger service. The steam generator uses the same fuel tank as the engine. On B units the area where the cab would be leaves plenty of room for a large water tank in the car body. A units have a limited water capacity which is why on the Southern Pacific, standard F7 A units didn’t have steam generators and F powered passenger trains usually used an ABB combination.

The ice breakers were bent using the drawing shown in a previous post. The drawings came from an HO Hi-Tech Ice Breaker set. The drawings were scanned and blown up to ¼” scale. The same was done with the cooling pipes on the roof using drawings from an HO Highliners F unit kit.

Bob: If you would like a copy of the drawing, send me a private message.

The pipe was bent from 1mm brass wire. The flanges (missing from the previous post A unit photo) shown in this photo where the pipes go through the roof are Precision part #5155, which is a packing gland for the valve stem on a steam locomotive cylinder block. I had to cut off the back, then drill it.

Hope everyone had a good Christmas.



Robin -
Thanks for posting the additional photos. The web maestro did his magic to fix the problem with attaching photos.

You will have a beautifully-detailed locomotive when complete. And yes, I would appreciate a copy of the cooling coil drawing, PM sent. Please keep us posted on your progress for this build.

All the best.



Thanks for your comments. I will post more pictures when I have something worth sharing. With my work load right now, I have very little time to work on my trains. I was hoping to enter the A unit in the “O Scale Trains” “Year of the Kit” competition, but as you can see, the entry deadline came and went with the unit not even half complete.

You asked a couple of questions in your private message which I thought I would answer here in case others might be interested.

As far as I can tell the cooling pipes were only added to F9 production units. SP never had any F9’s, except for F7’s which were rebuilt to F9 specifications (without the pipes). The pipes were very rare on SP units. I can recall seeing only one photograph with them. They may have been retrofitted to some units. They may have felt that black pipes on the roof while running under to desert sun probably heated the air rather cooling it. Other railroads sometimes used variations in the piping which suggests they may have also been retrofits. One railroad has one loop on one side of the fans and another loop on the other side.

Although these units follow SP practice, I purposely deviated in a few details. On the SP, only FP7 A units had steam generators; winterization hatches were very rare on the SP, as well as the cooling pipes; and SP didn’t use the extra horizontal grab under the train number board, although the Cotton Belt did.

I had an experience which reminded me of how uncertain research can be. On the P&D units, the main air reservoir is tilted with the forward end being slightly lower the the rear end. All drawings I’ve ever seen of F units, including EMD drawings in the F unit operating manuals show the tank as not being tilted. How could P&D make such an obvious mistake? A week or two after discovering that mistake I came across a photograph in one of my books about F units. It was taken from the erection floor at EMD, looking up at the bottom of an F7 A unit and guess what… The air tank is tilted! It may have been a change made after F units had been in production for a while. It might make it easier to blow condensation out of the tank. Now I wonder how P&D got it right with all the drawings showing it wrong.





Thanks for posting the pictures of your F units. They motivated me to get off the dime and get a set of A-B-B-A body shell kits ordered from P&D. Mine will be done in the Santa Fe freight cigar band scheme. Like you did with the ice breakers and piping, I’ll be scratchbuilding oversize fuel tanks, battery boxes, etc. by scaling up HO scale parts (High-Tech details). I’m looking forward to seeing more of your progress.


Doug Heitkamp
Centennial, CO



Thanks for your comments. I really enjoy working on the P&D units. They are fine kits, but don’t have much time to work on them right now. I’ll post more when I have been able to do more work.

I hope you will post pictures of your Santa Fe units as you go. Do you plan to add the red stripe that appeared between the blue and yellow? I always liked that version of the paint scheme.




My F unit body shell kits arrived today! What a great way to start the weekend. I’m anxious to get started on them. Unfortunately, I won’t be doing the early Santa Fe cat whisker paint scheme with the red stripe. I agree, it sure does look good and is a favorite of mine. I have sets of decals stashed away for the day I can start on some FT’s and use them. I’ll post pics once I get far enough along.

About your F units - Are you building your own underframes or using what comes with the stock P&D units?

Bob & David - Greetings! What did you guys use for the underframes, tanks, and battery boxes on the A&O F’s?

Looks like it’s time for me to get up to the Railroad Museum and start taking pics and measurements of the D&RGW F units up there.




Doug -

David and I bought complete kits from P&D. They came with a brass chassis, fuel tank, brass cast and equalized trucks, bolsters and (usually) a plastic simulated frame. My B unit did not come with the frame I-beams but that was easily solved with Evergreen styrene. The battery box door is molded on the side skirts, which we left intact. If you trim the skirts then you will need to scratch build a few details such as the rest of the fuel tanks, battery boxes, traction motor cables, etc.

I liked them so much that after building 3 I bought 6 more. All of mine are the single tower drive, which leaves room for P&D’s A-unit cab kit. There is a drive shaft that runs through the fuel tank that I don’t find objectionable. The dual-tower drives don’t have that shaft but the front chain tower prevents cab detailing. Also there is plenty of room behind the A-unit cab and above the motor (may want to trim the unused motor shaft end) for a big hi-bass speaker, either 1.77 or 2 inch diameter, in a sealed wood or styrene enclosure.

You can order any missing parts from P&D. If you need the exploded drawing, send me a PM with your email address and I’ll email it to you.

By the way, P&D sells two very nice cast brass grab iron sets.



My F units were also complete kits. All units are powered so that I don’t have to put too much weight in them for pulling a 14 or 15 car passenger train. The trucks included in the kits are brass and are the best looking Blomberg trucks I have ever seen.

I am using the cast grabs from P&D; they really look good. Check their parts listings. They have a number of other parts that you can add to your units, including nose mounted lifting lugs as used on later F units and winterization hatches, if needed. You might contact P&D and see if they are willing to put together powering kits for you. It might be cheaper than buying individual parts and it never hurts to ask.

If you haven’t already, I recommend you do a search on this forum. There are a number of very useful pictures showing how the A&O F units were built, including the 2" speakers mentioned by Bob. They will inspire you, as they did me.



The two inch speakers are a must.

I believe that they are grin generators for us model folks :smiley:



Thanks for all the info. I decided to go with the body kits and fabricate my own underframe/tanks/battery boxes in order to put all that I can into these from a model making point of view. I know it’s a harder way to go, but that’s just me. Inspiration for the project comes from the Santa Fe F units David Hussey did in HO scale.


What I am going to try is to have both trucks powered, but with the drive line above the floor/frame in the body. This is no problem in the B units. The powered A units will be the engineering challenge, at least under the cab end. I’ve also got 3 of the Red Caboose GP’s to do (I need a GP7, GP9, & GP20). I’ve purchased the GP9 re-power kits from P&D Hobbies with the brass trucks as well as the brass frames from Des Plaines for those. In addition I’ve purchased the Proto48 conversion parts for these trucks from Protocraft.

My plan is to modify the GP drive to fit in the F units. At a minimum, I’ll need to fab “short” towers to hold the upper gears. I’m currently drawing this stuff in AutoCAD and will be happy to share with everybody. I’ll be placing a follow up order with P&D to get the extras that I need.

I’d also like to add that I have enjoyed all of the posts that have been made in these forums. I’ve read them all. I really like the threads on fixing the P&D/Weaver Gear Towers and adding sound in the GP9. Nice work!




Doug -

By all means, let us see your drive train work as it proceeds.

I imagine you could lower the motor part way into the fuel tank to relocate both drive shafts. Serv-O-Link has a nice web-based calculator to find the proper shaft spacing for different sprockets.

By the way, the sliding Delrin shaft couplings can bind after considerable use. A little graphite can help.