It's been nearly a month since my last post in this series. In this time I got sick and been wiped out for a couple weeks. I was able to peck at a couple things, and have done some pre-production test installations in the last few days.
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| We're getting into Diaphragms, Weights, and touching on Draftgear. |
Again, this is all pre-production tinkering, production parts may change. The production steel weights have arrived, and I've used them whenever possible in this post.
Installing Weights
Underframe Mods
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| 75-CS Lounge frame with stock weights removed. |
In the last post, I covered flipping the pickups around to the other end of the car, but not really covering the changes and modifications needed to fit the new OwlMtModels 9040C Weight. The corner fences for the original weights are removed with my flush cutting sprue-cutters. There's also four tabs along the copper pickups, which I cut down flush.
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| Original planned insulation, but too thick now. |
Originally the plan was to insulate the steel weight from the pickups with some 0.010" or 0.015" styrene or washers. However, when the weight material was increased to 0.104", it means that we have to go down to tape-type insulation.
Weight Insulation
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| Insulated weight with blue tape. (note this is a prototype for future runs of these weights). |
Currently I've tested "blue masking tape" and clear plastic packing tape. While neither is official insulating tape, they have worked so far. Of course holes are opened in the tap for the centerline four large screw-mounting holes, the four small pickup alignment plastic pins, which all I want to do is have for alignment and to keep the pickups in alignment under the weight. The two 'pogo' contact pin holes are opened, but I actively wanted to keep the tape bits pushed into those holes, so the 'pogo's don't hit the weight.
Weight Specs:
Stock GGD Car weight = ~5.0ozOMM 9040D = Diner Weight = 9.6oz (max size for cars with no vestibules)
OMM 9040C = Coach/Lounge = 9.2oz (combined weight)
Modified Weight = 8.2oz (simplified weight with ends removed, for future OMM 9040 production runs.)
Modified Weight = 8.2oz (simplified weight with ends removed, for future OMM 9040 production runs.)
I'm going to briefly mention some of the weighting decisions. Ideally, in my experience, the ~80ft passenger cars in HO scale should be around 8-9 ounces. The MTH Daylight cars with full-width diaphragms seem to like 6-7.5 ounces for ~60ft cars, again bumping up the 4.5-5.0 ouch stock weights a bit, due to the diaphragms adding forces that want to derail the cars if they are too light when they are in contact from 'close coupling' operation on 40-50" radius curves.
Also in consideration on these cars is that the trucks, like the Daylight MTH cars, have very fine needle-point bearings. There's a limit to how much weight this type of bearing can handle without undue wearing and failure. Thus, I'm aiming for a 8.0-9.5 range of weights to operate with brass passenger cars or longer 15-car plastic passenger trains. Obviously, I'm wanting to do some test operations on friend's layouts, but I've not had time to do those tests as of the last week of Oct'26.
Also in consideration on these cars is that the trucks, like the Daylight MTH cars, have very fine needle-point bearings. There's a limit to how much weight this type of bearing can handle without undue wearing and failure. Thus, I'm aiming for a 8.0-9.5 range of weights to operate with brass passenger cars or longer 15-car plastic passenger trains. Obviously, I'm wanting to do some test operations on friend's layouts, but I've not had time to do those tests as of the last week of Oct'26.
Interior Floor Mods
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| Underside of stock 75-CS Lounge interior. |
The stock interior has a number of lateral ribs which will foul the new larger weight in the car. I roughly removed them with my flush-cutting sprue-cutters.
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| Underside of modified 75-CS Lounge interior. |
Then I cleaned up the remaining material with my Dremal with a composite cutoff disc. I also smoothed out the ejector pins and made sure the extensions of the interior detail parts are flush as well. I also take this opportunity to transfer the electrical 'pogo' pickup holes to the vestibule-end of the car via the holes in the weight.
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| Diner interior underside modifications. |
Note that the Diner and some of the other cars use metal walls, with long tabs through holes and bent over. I generally glued the metal walls in place after painting and then used the Dremal to clean off the extra material.
Fixing Window Sills
There's been some debate on-line about the lower window sill's size. I started modifying this part of the GGD cars in the last part of this series. In this post I'm wrapping up the current work on this part of the kitbash.
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| SP Diner with modified window sills needing paint touch-up. |
While I did mostly hand-carving with a sharp No.11 blade on the Diner, I switched over to using my flush-cutters to remove the bulk of the sill 'block' and then scraping with a chisel blade at near 90 degree angle to the body on the Lounge. Then cleaning up the Diner a bit more before touching up the paint.
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| Left side of the Lounge waiting for touch-up. |
The four windows for the bar and barber room are probably the most tricky to do without over-cutting and leaving a off-plane marks into the body.
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| Right side of the Lounge waiting for touch-up. |
This car wasn't so bad to do with the chisel blade cleanup on the window sashes... While I'm not quite mentally ready to deal with the 72-IC Subs just yet, they are not impossible to do.
Patching Exterior Paint
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| SP 10105's right side with patched window sills. |
I went ahead and started decalling this Diner as the SP 10105, which will need a Green scheme interior... so my tan painted interior in this model may need to be swapped to one of my other diners. Oops. One of the "1" also moved on me... so I'm considering lifting these decals and renumbering the car as 10112 or just fixing the "1".
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| Diner's left side with patched window sills. |
In these photos, I knocked loose the painted stock windows for the kitchen, so one of the other modifications I'll do when the windows show up is seal and paint over the three lower left kitchen windows, and get that paint patched up before the window glazing goes into the rest of the car.
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| Lounge's left side with patched window sills. |
This first Lounge that I'm working on is becoming the SP 2934, one of the cars which has the Green Scheme interior applied, so that will be fun to apply too.
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| Lounge's right side with patched window sills. |
The right side of the car doesn't have the reporting mark and type decals applied yet, but it will all come together eventually.
Different Ends, Different Coupled Lengths
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| Diner 77-D-3/4 (Top) and Lounge 75-CS (bottom) |
It turns out that GGD didn't use the same coupling length on the underframes, even though they used the same parts for the swing-extending draftgear, they installed different length Kadee couplers, which I think may explain some of the issues with the longer couplers on the dining cars having more vertical problems than the other car types.
This is requiring OMM's draftgear parts to have at least two versions for proper close-coupling for the Diner and non-Diner GGD V2 cars. There will probably need to be another version for modelers desiring more 'extended' installations.
77-D-3/4 Diner Diaphragm Test Installation
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| Drilling Jig used on the Diner's ends. |
I up-sized the drill bits from the Hi-Tech's instructions 1/32" drill (0.0315") to No.56 (0.0465") drill bit, to account for the extra rubber on the parting line of the rubber leaf springs. The OMM drilling jig is designed to be flipped over and act double-sided so that I can use it on square-ended Diner or the "Angle-ended" Lounge, or other cars in the series of cars. The large tab at the bottom is designed to key into the coupler opening in the shell and align it before drilling the holes.
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| OMM 4099 Hi-Tech Diaphragm drilling jig (for "Common Standard" Hi-Tech 9000-series diaphragms). |
Given this is the first pre-production and testing of these parts, the production jig prints will have clearance notches for the angled grab irons on the end of the dining car.
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| Rubber leaf springs installed on the Diner. |
Notice the light scribing from the back of a No.11 Xacto blade which I ran around the inner edge of the jig to mark the opening in the end of the car for the outer bellows of the Hi-Tech Diaphragms. I'm planning to 3d print new 1937 'porthole' doors, so I can remove the original 1920s wooden panel doors completely.
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| Body-side bellows installed on Diner body. |
The interior profile of the jig is designed to fit inside the Hi-Tech diaphragm, as most installations, I've found that I need to use a Dremal with burr bits to clean out a bit more material so the bellows of the diaphragm can properly compress and not 'go solid' against the end of the car, which can lead to derailments from the two cars binding against one another through the locked up diaphragm.
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| Drilling out the doors on the 77-D-3/4 |
Unfortunately, I didn't get a picture of diner body that I was drilling out, so this is a mock-up picture using another stock car body.
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| Kitchen end, diaphragm mounted. |
I drilled about 6-8 holes with approximately 1/16" between the holes. My flush-cutters worked well to connect the holes, then No.11 and No.17 Xacto blades were good for cleaning up the inside edges. I'm doing this for 3d printed more modern doors to fit.
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| Direct end view. |
The interior wall took the hits from the drill... oops. Should have probably take the shell off before doing the drilling, note for future diner modifications. The 'late' 1937 rebuild of these cars, saw the wood panel door replaced with 'art-deco' style doors with round window end door will cover up the various levels of interior and weights.
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| Other side of the Kitchen end diaphragm. |
Lastly, I'll airbrush the SP Dark Olive Green paint over the diaphragm bellows and then apply the etched metal striker plate. Normally, I like to install the diaphragm first, so I can see where the mating line of the diaphragms will be, then fit the draftgear and coupler to get a good close coupling, but not "too tight" of spacing.
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| Bottom view of the diaphragm and coupler draftgear. |
This draftgear application is the early pre-production 3d prints, which will have some small changes before going into full production version.
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| 77-D-3/4 with Hi-Tech Diaphragm, slightly too short of draftgear. |
The diaphragm on this test car came out slightly too long compared to the length of the draft gear, putting the coupler a bit too short. Normally I want the coupler's knuckle inside edge to be slightly visible beyond the striker face. This installation will result in the diaphragm being a bit tighter and needlessly press about 0.015" of force into the coupled joint.
75-CS Lounge Diaphragm Test Installation
On the Lounge, I didn't need to drill out the lounge-end's exterior door... as it turns out to be a seperate piece, which is glued in, and can be knocked out fairly easily.
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| Next drilling target up... oh, wait, it comes out! |
In this photo, we can clearly see the holes drilled from the jig into the end to fit the rubber Hi-Tech diaphragm leaf springs.
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| Stock Lounge with the stamped door installed. |
Here's what the interior of the stamped metal door plug looks like.
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| Surprise! - Knocking out the end door. |
Note that I've already installed the Hi-Tech rubber leaf springs in this photo. I actually planned to start drilling on this door, before it popped and jammed in the opening like this... so I stopped drilling and just popped the door out.
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| Removed stamped metal door from lounge-end. |
I'm not sure why GGD went with a stamped metal door, instead of molding the end of the car in plastic. I'm guessing that it was to keep the tooling minimal on the body. The cars with angled-ends have open ends, the diner which has square ends was another mold and had the closed doors molded in.
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| Diaphragm - Lounge-end, left side |
The Lounge end of the car will also get a 1937 "porthole" door 3d printed to fit in the opening.
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| Diaphragm - Lounge end, right side |
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| Diaphragm - Vestibule end, right side |
The vestibule end of the car will still remain open, but still needed the inner edge of the door opening enlarged to allow the bellows to fully compress against the car's body-side bellow ring.
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| Diaphragm - Vestibule end, left side |
Like with the Diner, next will come some touch-up painting on the diaphragm and getting the etched strikers fitted.
Coupled Length Checking on Diner & Lounge
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| IC-72 stock (left) coupled to modified Diner (right) with diaphragm installed. |
The stock "Sub" on the left, has the stock draftgear system which includes about 0.045" extra distance between it's diaphragm striker and the median point of the at-rest coupler knuckle. It fits nicely against the slightly too short Diner diaphragm and pre-production draftgear, so again, this combination works. Unfortunately, if the joint is tensioned, the 'Sub's draftgear extends and stretches out, opening the gap of about 3/16", which is way more than looks good.
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| Coupling of Lounge on the left and Walthers 10-1-2 (kitbashed to 10-1-1) on the right. |
I just reached over and grabbed a typical Walthers HW sleeper that I had to hand to check coupling distance on the Lounge.
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| Diner to the left, Lounge to the right |
Here's the way these two cars would be coupled in my Owl or West Coast consists. The longer coupling distance of the Lounge pairs nicely with the Diner's short coupling with the pre-production draftgear prints.
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| Lounge to the left, Walthers Solarium-Sleeper (Mission Delores) to the right. |
In the Owl, the full lounge was followed by the "Mission" series "Solarium"-Lounge Bedroom sleeping cars, with their lounge space running wards the front. Again, the longer coupling on the Lounge, actually is too long for 'close coupling' on this pre-production testbed car. Ideally, I'd want the coupling distance about 1/32" tighter. Of course this if for my cars that like to run on 42-48" radius curves. This gap would be about perfect for down to ~30-36" radius operation.
In Closing
This post has turned into a bit of monster, but I guess that's what happens when I feel I have no material for nearly a month and was sick for several weeks of that time too.
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| I know everyone wants the new draftgear... |
I'm side-stepping the details of the Draftgear prints, because I'm tweaking the design of those parts to make their installation more reliable and consistent that I've seen with these pre-production parts. So when I get the next round of these parts I'll be making a more detailed installation post on them.
The windows have had some snags, but I'm hoping to have some new samples of those soon too. I'll also be getting into repainting the interiors of the cars, choosing car numbers, etc to make my models into.
Jason Hill
The windows have had some snags, but I'm hoping to have some new samples of those soon too. I'll also be getting into repainting the interiors of the cars, choosing car numbers, etc to make my models into.
Jason Hill
Related Articles:
Golden Gate Depot Harriman 2.0 Review - Out-Of-The-Box - Initial thoughts on the new cars.
OwlMtModels Announces development of Golden Gate Depot "Upgrade" Parts and kits. - From Sept 8, 2026.
GGD "Harriman" V2.0 Upgrades - (Part 2) Beginning Prep Work to Upgrade - Starting to make modifications to GGD V2 cars, as first pre-production OMM parts arrive.
SP Passenger Car Interior Colors - August 1950 Assignments - Data from Bob Zenk's collection and consolidated by Jason Hill for modeling interior of our passenger cars based on SP's own Aug 1950 paint drift cards.