Saturday, August 6, 2016

Building SP 5199 (Part 5)

In the last post of Building SP 5199 (Part 4) I roughed in the couplers, this time we finish the mechanicals and the outside of the car's paint.

Right side of SP 5199 in the afternoon sun

Couplers and Low Riding Cars

Checking the car against the Kadee Coupler Height Gauge, it shows the car sitting about 0.025" high. I temporarily made some 0.015" shims of sheet styrene to lower the coupler boxes.  I usually don't like to use more than one shim, as it makes the car ride too high.   I did a bit more investigating around the underframe.  As I suspected earlier the plumbing running under the bolsters is fouling the trucks.

I cut away the plumbing above the trucks.  This keeps the details under the main body, but again like the detail parts of the bolsters, it clears up the space above the trucks.  I cleared a bit of extra material from the edges of the center sill flanges to clear the arc of the truck swing with my Dremal burr tool.  The truck bolsters are still too high, I shave them down with the Dremal as well.about 0.020".  Checking the ride height every so often against the Kadee gauge.  I kept the 0.015" Kadee shims.  The shim will provide a good bearing and also will allow the truck to track over vertical curves.

With these modifications the car now rides at the correct height.


SP 5199 with decals overcoated and flat finish applied - Windows still masked.

During the finial building steps after the decalling, there were some chips on the painted grab irons and stirups.  The modifications for the ride height also caused the underframe to have many rub marks and was much in need of touchup.

The interior was painted at this step as well.  I didn't have the exact color match to the US Mail's standard cream color for the mail apartment, so instead I used Tamiya Wooden Deck Tan.

Touch up work around the grab irons was done with StarBrand Dark Olive Green and I repainted the underframe again with my off-black mix.  I wanted to touch up the inside of the side sheets as well.  I put the underframe back into the body.  Using a piece of plastic card-stock to mask off the finished outer car sides I shot the black mix around the inside of the car side.  Taking the floor out again, I did some additional touch ups where the frame details masked the touchup work.

Flat Finished undrframe of SP 5199, the axle-belt electric generator will be installed later.

I also painted the trucks and wheels with the black mix.  The StarBrand paint leaves a glossy finish, so I over spray the underframe and trucks.  The Flat Finish really leaves a dead flat finish, which is not what we want for the car sides.

Many SP headend cars did weather quite heavily and would look pretty flat, this RPO was most likely repainted in late 1947 or 1948.  The car's paint then would only be 4 or 5 years old.  The car was repainted in 1954 or 1955 into TTG.  I don't want the car to look totally decrepit so.  I used Testors Wet Clear to overcoat the car sides and seal the decals.

The Wet Clear is super glossy, which is a bit more glossy that would look appropriate.  The car is basically pre-weathered by using the off-black color for the underframe and roof.  To blend the finish of the car together I dust on the flat finish to the carside by bouncing it off the spray table.  I wanted to make the car look like it's faded and flat from the road dust.  The flat finish comes about half way up the bottom side sheets of the car and then fades out as it goes up the car side back to the high gloss.

After each of the rounds of touch up and over spraying I left the car to "gas off" in the warm summer heat for a day or so.  I did check in on it every hour or two, making sure the parts were not getting too hot.  The StarBrand paint is a lacquer and doesn't need to be "baked" like enamel paints, however I do like to be sure the paint has finished nice and hard before putting down any more paint.

The Unmasking

Windows demasked looking into the RPO section from the right

With the body off I carefully started removing the masking from the pre-laser cut windows.  With the heat from the car being out in the sun drying, I think the masking also baked on too!  It was harder to get off than I remember from doing the windows on the SP 5124.  It took the better part of an hour to do.  Being VERY careful not to scratch or cut through the masking onto the clear window glass.

One window popped out during this process.  I removed its masking and then remounted it with Testors Canopy Cement from the inside with the window in place.

What's Left on the Outside

The car still needs to have the door windows mounted.  The diaphragms are also riding a bit low on the couplers.  The baggage-end coupler is sometimes fouled and will not center by the striker.  I will be fixing this issue with a small wire spring to tease the striker up toward the top of the free-play in the diaphragm, but I'll leave that for next time.

Interior Progress - CAD and 3D Printing to the Rescue?

The interior's the next major project on the car.  If interior lighting is not going to be mounted, then this portion of work really wouldn't be seen.  However as I plan to put lighting in the car, that pushes the issue of scratch building all the bag racks and letter cases for an RPO, which is a daunting task.

Current status of car's interior

I'm not really an advocate of doing **EVERYTHING** with 3D printing.  While there are amazing models being made with it, often there's a LOT of clean-up work to do.  Sheet styrene can make thinner parts and we're sure of the long term stability of styrene and ABS plastics.  I do believe there are certain times that a one-off 3D print will really make a project shine, I feel this will be one of those times.

I spent about 2-3 hours drawing up the car body and floor in quite a bit of detail.  This is critical to making following parts fit correctly.  I even modeled the styrene blocks I used to mount the body to the floor.

Pouring over the standard RPO drawings, photos of the interiors, and the video linked in my RPO page on this blog I was able to work out what the interior of a 30ft RPO Apartment should look like when it's working.  Rivarossi has made interiors for their RPO cars, however they worked only off the drawings and didn't read the fine print that says that both sides of the car had "Bag Racks" and both sides also had "Paper Boxes" along the windows.  The Bag Racks folded down off the interior wall where the windows are and the Paper Boxes were bins over the windows with a door to dump the contents of the bin into a bag suspended from hooks at the bottom of the bin when dumping the bin.  The interior of RPO cars were truly an amazing exercise in practicality and form matching function.

Additional bags and modular sorting tables could be set up on center floor stanchions to work the Bag Racks, Paper Box bins.  The center stanchions were cut 8" shorter so there was room at the letter case at the car-center end of the apartment.

In the Baggage section I drafted up the desk, stove, enclosed toilet partitions, water cooler, safe, and electric locker.  The baggage door windows and the one center-car window will be the only way to view these, so again, it doesn't have to be too fancy.

The drawings are based on plans for SP 5164 & SP 5166, but it's the only 69-BP-30 floor plans shown in the SP Passenger Cars vol.3: Head End Equipment book, so you work with what you have.  Also as mentioned in the RPO video, each route could have different setups for the sorting table, etc.  While it would be esoterically cool to be able to look up what the proper setup for the Tehachapi Mail (Nos.55 & 56) or the Owl (Nos. 57 & 58) RPO would be in 1952, I'm not going to loose any sleep over it!

I didn't bother drafting the storage mail stanchions or the RPO door dividers, those will be either made from scratch or omitted if they can't be seen from outside the car.  I do want at least something resembling the letter case as viewers might be able to see into that part of the car with the interior lighting.

Dropping the Mail

Where we're leaving it now - Left Side

Where we're leaving it now - Right Side

That covers it for Part 5.  Building SP 5199 (Part 6) will be coming along when the 3d printed interior parts arrive, probably about a month or so.  I'm sure some of you are probably ready to go "Postal" with all these posts about RPOs...  I hope to work on some other blog projects for the next few postings.

Jason Hill

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  1. I have been following this build with excitement. Excellent work Jason! Will your 3D prints of the RPO interior be available for purchase on Shapeways? - Phillip J

    1. The first round of the prints is done now, Enough to do the 5199. I need to do some changes before it could be sold. I did talk to my friend about producing them. I believe if we do come to an agreement, they will be made to order, fairly limited numbers, and with a fairly long lead time compared to items I keep in stock.

      I hope to install the RPO interiors soon and get a blog post up with it soon.


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