GE Kitbashes Part II

Phase 3

Not the Rapido B36-7

Now that Rapido has delivered the B36-7 in HO scale, the Phase 3 Bxx-7 frame is a reality. Atlas already covered both Phase 1 and Phase 2 frames with their B23-7 and B30-7 models. So what exactly are the differences between the Phases? The big change is the frame length and truck centers, even though it's a pretty small change as locomotives go.

Michael Eby's Dash 7 Phases page contains a wealth of information. Michael cites Will Davis and David A. Davis' blog for some in-depth prototype information. To recap Michael's data, the Phase 1 frame is 62'-2" over the pulling faces with truck centers at 36'-2". The bolsters in Phase 1 are 13'-0" from the pulling face of each end. Phase 2 kept the same length frame, but moved the rear truck one foot closer to the coupler for 62'-2" overall, front truck 13'-0" from the pulling face, rear truck 12'-0" from the pulling face and 37'-2" truck centers. Phase 3 shortened the frame by one foot overall, bringing the pulling faces, pilots and stepwells six inches closer to each end and and bringing the rear truck in a corresponding six inches for 61'-2" overall, front truck 12'-6" from the pulling face, rear truck 12'-0" from the pulling face and 36'-8" truck centers.

What does the Phase 3 frame do for us in HO scale? Aside from the B36-7, with the Rapido model there is now a frame for late B23-7, B30-7, B30-7A and B30-7AB models. The Southern B30-7A1 is its own thing on a frame different from everything else, but the Burlington Northern B30-7A1B units share a Phase 3 frame with the earlier B30-7AB.

The Rapido models aren't cheap -- nothing in HO scale is at this point anymore -- so who's going to use them for kitbash fodder? Not me I can tell you that! But some folks might be motivated to tear off the shell of their model and replace it with something else to help them model a B30-7A or a late B23-7 or one of the B-unit versions Burlington Northern had. If I were a betting man I'd put money on Rapido offering these models on their B36-7 frame at some point in the future. In fact, when they were showing the test shots of the B36-7 they hinted at these future releases by showing fuel tank variations tooled for Missouri Pacific and Burlington Northern, neither of which had the B36-7. 

So if not Rapido, what's the path to modeling a Phase 3 Bxx-7? 

The Method

Long before I'd ever heard of the Rapido model I worked up some drawings of the various Phase 3 hoods. One thing led to another and I started drawing some Phase 1 and 2 hoods. And fuel tanks. And details. Anyway, Atlas got a few things right with their Phase 1 and 2 models, so I didn't see any reason to reinvent the wheel there (at first). In particular I liked the way the radiator was rendered with cores molded as part of the body and a photoetched metal screen insert with frame that snaps in place on the radiator. Now that KV Models offers an etched part for the Atlas U33C/C30-7 radiator, which is larger and better proportioned than the B23-7/B30-7 radiator, I've begun adapting this etched part to a revised 3D printed radiator section. 

Atlas is to be commended for their B30-7 cab. I covered what makes it good and where it misses in a previous blog. They have also recently started delivering their U33B/U36B model with a revised cab that addresses these shortcomings. I couldn't wait for that so I designed a cab with better fidelity to the prototype some time ago. It comes with numerous options covering the Universal Series through the end of Dash 7 production. I started printing these cabs as flat kits through Shapeways but over the past year or so I've been printing one-piece resin versions.

Now as far as the rest of the Atlas model is concerned -- the hood contour, the heaviness of latches and other details, the fuel tank and reservoirs, the high short hood -- well, not so good. These things are passable in a factory painted model I suppose (nope, not that high short hood), but after kitbashing the Southern Pacific B36-7 above from an Atlas C30-7 body I figured I could do better. This has led to a lot of drawings of Bxx-7 hoods. A LOT of drawings.

GE B36-7 B-unit wreck rebuild, one of many drawings

The Atlas sills are also very nice and they are easy to shorten by cutting out six inch sections near the stepwells. The B36-7 kitbash makes a good case for using the Atlas sills in a Bxx-7 build. The Southern B30-7A1 is it's own thing worthy of its own blog, but was also able to make use of the Atlas sill by lengthening it just aft of the step down from the battery boxes. Phase 3 sills have a "long, short, long, long, long" pattern of access doors on the conductor's side under the cab, compared to the Phase 1 and 2 pattern of "panel, short, short, long, long, long" access doors. This is easy to model using a donor sill to harvest the long access doors. However, this process of cutting up spare sills gets a little old and mistakes can be made, so I've been drawing up variations on the sills to be able to print every version without cutting anything. Again with more and more drawings.

Atlas Phase 2 subbase modified to Phase 3 (moving the stepwells inboard remains to be done)

So if I'm keeping the Atlas sill and radiator part, what am I replacing? Everything else. Well, almost. I do like using the Atlas coupler boxes. But who knows? I might start printing those, too.

The Frame

This is the wildcard that prevents using an Atlas frame. The Phase 3 frame is not only shorter in length, but the truck centers are different from both Phase 1 and Phase 2. I've seen other people scratchbuild frames out of brass or cut up diecast frames and piece them back together with pins, screws or strong glue. I could probably muddle my way through one or more of those methods but I doubt I could make it repeatable. So instead I dealt with custom frames by drawing them in 3D and printing them in nylon through Shapeways. This allowed me to model the B39-8 demonstrator, B36-7 and create a dummy frame for a spare Atlas Phase 1 shell I had. This method also allows me to model any frame with any truck centers, which means models are on the table now that only existed as demonstrators or were built for only one railroad.

Shapeways' nylon is a rough material but it is strong. It also doesn't present an opportunity to show detail so the fuel tank and reservoirs are printed as separate parts to cover the frame much in the way a pretty or exotic veneer wood is used to cover a less expensive and less attractive substrate wood. The nylon material does not offer much weight though so it has to be added somewhere. My first attempts to fill the fuel tank area with weight resulted in the frame sagging, so it became clear the frame would either have to be reinforced or the weight would have to be located in the body shell. The thicker frame seemed to do the trick but it still couldn't support much more weight than the Kato HM-5 motor and drivetrain so I glued lead bird shot into the inside of the body shell.

First generation nylon frame with Life-Like P2K Athearn-clone AAR B trucks designed for Atlas B30-7 fuel tank

The first variation on the frame involved using the laser cutting vendor Send Cut Send. I was able to get thin sheets of stainless steel cut to my dimensions for a good price. I removed a corresponding amount of thickness from the nylon frame model and glued the frame to the steel part. The fit was excellent since both Shapeways and Send Cut Send do very precise work.

Laser cut stainless steel frames from Send Cut Send

Hybrid nylon and stainless steel frame with Athearn trucks and 3D printed B30-7A1 fuel tank from Shapeways

Once I started using MP Scale Models as my printing vendor instead of Shapeways I was able to adapt the frame design to resin instead of nylon. This results in a much smoother appearance. The resin material is also easy to cut, sand, drill and tap. Like the nylon material these resin frames don't have much strength on their own but together with the laser cut steel frame they are quite strong.

Hybrid nylon/stainless frame on top with dimensionally challenged Atlas fuel tank and skinny but too long reservoirs;

hybrid resin/stainless frame on bottom with resin fuel tank and reservoirs

Hybrid resin/stainless frame with resin fuel tank and reservoirs and Athearn trucks with Atlas/Kato FB-2 sideframes

To date all these frame variations are designed to use a Kato HM-5 motor with flywheels, Athearn drive shafts and Athearn trucks. I am working on versions that will use Atlas and Atlas/Kato trucks (such as the AAR B and FB-2 found on the early C424 and U23B models) as well as Atlas and Athearn motor mounts. A-line makes a universal hex drive shaft kit so that is an option if the Athearn hex shafts in various lengths are unavailable.

Trucks

So far I've been working with Athearn and Athearn clone trucks on these kitbashes. They are widely available and the design hasn't changed over the years. Not only that but the Athearn Blomberg sideframes are legendary in their proportions and detail and unmatched by another manufacturer. For SCL/Family Lines/CSX modelers this is great. And for Conrail and Santa Fe modelers the former Life-Like Proto2000 AAR B trucks are a drop-in fit. I'm not certain but I believe Athearn has made their own AAR B truck for the former MDC RS-3, but I have not seen these. Both the P2K and MDC AAR B truck model the longer wheelbase of the prototype accurately whereas the AAR B trucks found on old Athearn U28B, U30B and U33B models are a shortened version of the sideframe adapted to the Blomberg truck.

Blomberg trucks vs. AAR B trucks; Life-Like P2K on top, Athearn on bottom

The FB-2 trucks commonly found on most of the Bxx-7 prototypes have been made in HO scale by Atlas/Kato for the U23B, Atlas (China) for the B23-7/B30-7/B40-8 and now by Rapido for their B36-7. Smokey Valley made FB-2 sideframes designed to fit the Athearn Blomberg truck, but they aren't much to look at and they did not fit the truck very well. So I set about ways to correct this problem by adapting Atlas and Rapido sideframes to the Athearn truck. Atlas parts are generally available either from Atlas directly or other third party vendors but Rapido does not offer parts to my knowledge. However, Rapido made a mistake with their original B36-7 release and put the wrong sideframe variants on some of their models. To correct this they offered anyone who bought one of these models a full set of replacement sideframes. I was able to buy some of the "incorrect" sideframes from Rapido customers and adapt them to the Athearn truck. While these are good solutions to adapt existing parts the obvious solution is to draw the FB-2 truck and simply print new sideframes to fit the Athearn truck or the older Atlas/Kato truck.

The hideous crime against humanity that is the Smokey Valley FB-2 sideframe in the foreground, Atlas in background

3D printed adapters for mounting the Atlas/Kato FB-2 sideframe on Athearn trucks (these also work for Atlas China parts)

3D printed adapters for mounting the Rapido FB-2 sideframe on an Athearn truck

The Hood

The long hood and nose are the other parts I'm replacing. These are intended to fit the Atlas sill and (until recently) reuse the radiator parts. As I mentioned above an improved radiator part is now being tested to fit the KV Models etched grille.

When I originally started printing through Shapeways I learned quickly the way to get the best results was to design everything as a flat kit. Flat kits were these awful flash-filled ill-fitting things from the 80s that required more work to get usable parts than it did to actually assemble the kit. But the flat kits I've designed and received from Shapeways are nothing like that. If I must heap praise on Shapeways it's for their ability to deliver parts printed exactly the size and shape designed. When I've found a part that didn't fit as intended it turned out I made a mistake in the design. The flat kits I've printed at Shapeways go together exactly as designed and the parts fit quite well whether it's a caboose body or a B30-7AB shell. 

Where I've had a bit of trouble with Shapeways is printing large flat parts. There is a tendency for larger parts to warp so I found that breaking flat kits down to smaller interlocking segments helped keep things square as the kits were assembled. 

B30-7A1B body kit printed by Shapeways

B30-7A1B body kit printed by Shapeways assembled on modified Atlas sill and custom frame

The other problem has always been the price. These kits are not cheap. And after printing in resin the Shapeways acrylic material leaves a lot to be desired in terms of the finish. So the natural progression of the flat body kit is the one-piece resin printed body shell. 

B30-7AB body shell printed by MP Scale Models on modified Atlas sill and custom frame

Like the Shapeways kits some effort must be made to avoid warping but the ease of construction and quality of the finish makes that trouble worth the effort.

With GE models in particular there are so many detail variations within the different phases that it's cost-prohibitive to make every detail for every prototype. Rapido found themselves embroiled in a controversy over a stepwell variation specific to Seaboard when they promised accurate B36-7 models but ignored that variation because tooling up a separate sill part was too expensive. This doesn't have to be a concern with 3D printed parts. In fact, ifwhen there's an error or mistake made in the model it doesn't have to be forever. It can be easily corrected and new parts printed. No expensive tooling must be thrown out and replaced at a great cost. I have made my own share of mistakes (and then some!) but when I catch them I fix them. 

This B30-7A1 nose looks great against the cab, but it's too short and forces the cab too far forward. No sunk tooling costs to absorb and no errors to live with. The CAD file has been revised and a replacement is headed for the printer.

B30-7A1 cab and nose printed by MP Scale Models on modified Atlas sill

...but why male models?

You serious? I just told you that a moment ago.

For somebody who's not reinventing the wheel, it sure seems like there's a lot of reinventing going on. There may be something to that. The fact is, the more I looked at the Atlas Bxx-7 model the more I found to improve. There's no need to address the drive or the trucks, the cab is pretty good and the sill, steps and handrails are just fine. And the Rapido model, while it's an improvement in many ways over the Atlas model, it's expensive and doesn't give many options for modeling other Dash 7 variants (yet). 

But probably the biggest motivator is the cost. If I want to build any of these models I have to start with a powered Rapido model plus a pile of 3D printed parts or I can start with a pile of Atlas parts and a pile of 3D printed parts plus a motor and some trucks. Atlas parts are still cheap but the cost of the 3D printed parts is coming down while the quality keeps coming up. There's not much I can do about the cost of motors and trucks, but it's easy to find good deals on used models on ebay, train shows, swap meets, Facebook and so on. There's no reason why the guts of those used models can't be adapted to a new model.

So that's the future for now: keep on making drawings, making better parts, adapting the 3D printed parts to the good stuff that's out there already. I don't see myself making ready-to-run models out of this adventure. I may not even be able to offer complete kits. But the concepts behind this mess of cut up models and printed parts are viable, repeatable and scalable so that anyone with the right tools could do it.

Low-cost LED Lighting for HO scale Locomotives

Like many of you I have both old and new locomotives in my collection. The newest of these models have (literally) all the bells and whistles, headlights and warning lights that the prototypes had. The old ones, not so much.

Factory-installed incandescent bulbs in Athearn RTR SW1500 (foreground) and SD40-2 (background)

It would be nice to have enough money to just purge all the old models and replace them with all new models so the entire fleet would have lights and whistles and bells. But even then many of the models I have simply aren't available in a new version, and many more I've had to build, detail, paint and weather myself.

Custom built and painted diesels ready for headlights

A better solution than complete replacement of the fleet is to add those lights to the older models. I won't get into the debate over sound vs. non-sound decoders, which brand is better than the other, or whether incandescent bulbs or LEDs look more like locomotive headlights.

I like the NCE decoders I have because they work well, they allow the lighting functions I want and they are inexpensive. As far as lighting is concerned suffice it to say I've chosen LEDs. There are many companies who sell prewired LED lighting kits made specifically for HO scale locomotives and many of them are quite nice.

With few exceptions they are also not cheap. So if you're like me and you put off installing lights and decoders until you had forty locomotives, the prospect of spending all this money is anxiety-inducing. At first it was looking like I was going to be on a five-year plan to get lights in all my diesels.

A fellow modeler recommended the LED lighting kits sold by a certain railroad-modeling YouTuber (YouTubing model railroader?) on ebay, so I decided to try some for myself. They were inexpensive compared to every other option I could find and were well made if very simple. I installed the LEDs in one of my models and decided the concept was solid.

LEDs from ebay installed in a custom built and painted Athearn SD40-2

For $29 you get 15 LED assemblies with resistors (you have to solder them to the wires). So for the mathematically challenged of us out there, that's $1.93 per light and your run-of-the-mill locomotive needs four.

They worked great so I figured this is how I would solve my lighting problem. But after a couple friends experienced customer service issues with the ebaying YouTuber over these lighting kits I decided to make my own rather than roll the dice and end up with product I couldn't use. I figured I could get the cost lower than two bucks per light and I was right.

The raw materials are simple:

• prewired 3500K warm white 0402 or 0603 LEDs
• small diameter heat shrink tubing
• 1.5mm / 0.06" diameter fiber optic rod
• 820ohm 1/4 watt resistors

I bought all these components on ebay and spent just over $70 for enough LEDs, shrink tubing, fiber optic rod and resistors to assemble and install 200 LEDs. $72 ÷ 200 LEDs =  $0.36 each. $1.93 vs. $0.36 might not be much if you're only going to light one or two diesels, but it adds up quick, especially when you have Seaboard and Frisco or Southern Pacific diesels with multiple lights on each end.

The process to make the LED lights is very simple. I bend the wires so they point "behind" the face of the LED and twist them together (it makes handling the LED easier). Next I place the LED against a 1/4" length of the fiber optic rod and slide them together inside a short length of shrink tubing. Then I hold the assembly over a candle until the tubing shrinks to hold it together. I use fingernail buffing sticks to sand and polish the end of the fiber optic into a lens shape. I tried doing it with heat from the soldering iron or candle and the results were just too inconsistent. Here's a bundle of them after putting them together:

Completed fiber optic LEDs ready for installation

Before installing the lights in a model I solder a resistor to one of the leads of the LED. This is not required if the decoder is set up for LEDs and is equipped with resistors, but the majority of my decoders are NCE DA-SR or D13SRJ/D13J.

Installation is simple: from the inside of the body shell insert the fiber optic rod into the headlight opening. I use a no. 53 drill bit to create or resize the headlight opening so the fiber optic rod is a press fit. I secure the headlight with a tiny drop of CA. If you're not comfortable using CA other less permanent adhesives will work fine.

SP B36-7 shell showing LEDs with resistors installed and soldered to NCE DA-SR decoder

Once all the LED assemblies are fitted to the shell, solder the leads to the appropriate pads on the decoder or locomotive's circuit board if you're using a plug-in decoder. Before I attach the shell I test the lights to make sure everything works. If I am satisfied I reattach the shell and program the lighting effects appropriate to the locomotive.

Upgraded Atlas B40-8 with new headlights installed in nose

One thing I like about these lights is the ability to customize the installation. The bundle I showed above works well for 90% of the installations I encounter. But sometimes the light opening is in a tight spot. The GP60 demonstrator below is one example of this. The cab headlight is mounted in the roofline, so the fiber optic has to be bent to fit up inside the housing. I accomplished this by using the candle to achieve the desired bend, then shaped the lens and cut the rod to length. Then I assembled the rod and LED inside the shrink tubing and heated the assembly together. Once I had two identical LED assemblies I installed them in the headlight housing.

Headlights installed in 3D printed cab and nose housings

Upgrading Model Die Casting's Gunderson 4700cf Covered Hopper

I grew up in the shadows of some of the largest grain silos in Texas. Back then they bore the names Union Equity and Far-Mar-Co, Continental and Louis-Dreyfus. Everywhere in Fort Worth were grain trains, some with hoppers all painted alike and some with cars in a rainbow of colors. Railroad owned cars were pretty boring to me then. What really caught my eye were the light blue, brilliant yellow, bright pink and deep orange elevator-owned cars. My first custom painted model was an Athearn ACF Centerflow covered hopper I painted baby blue and lettered with Herald King PR-43 in the Farmers Co-op scheme.

Eventually the railroad owned cars would grow on me, especially those of Burlington Northern. BN had a large fleet of covered hoppers from the pre-merger roads as well as several purchased new in the late 70s and early 80s. As the 80s wore on BN acquired covered hoppers from several co-ops and elevators as well as some castoffs from Conrail. The additions to the covered hopper fleet couldn't be painted fast enough, even without the large name and logo applied to the sides of the car.

As I was seeing the fleet change in the late 80s I only knew there were two different types of covered hopper: the ACF Centerflow type and the ribbed side Pullman-Standard type. I knew this because Athearn made models of both (a crude PS 4740 and an even cruder ACF 5250). I really didn't start to dive deep into the differences between covered hopper cars until I started modeling the Bottineau grain train in the early 90s. As I described in the blog on Bottineau, I quickly became aware of the many different prototypes out in the real world and started collecting models of them from Intermountain, Accurail and MDC Roundhouse when I could.

Original MDC Roundhouse Gunderson 4700cf Covered Hopper

The Gunderson 4700 covered hopper kit from Model Die Casting's Roundhouse line was something of a transitional model between MDC's earlier less detailed kits and the more detailed models that would be released later in the 90s. Compared to say MDC's open hopper or boxcar kits, there was a real effort made to create a kit that built into a fully decorated model that looked complete. This model didn't have an unpainted underframe or brake details. Everything was painted and the lettering was crisp. The molded on stirrups and ladder rungs compared favorably with the Accurail ACF 4600 covered hopper released around the same time. The model had good bones, but soon it was surpassed by better models of different prototypes.

Like the Accurail ACF 4600 covered hoppers, I managed to collect a handful of these MDC Gunderson 4700 covered hoppers through the 90s and early 2000s. By the time Athearn had released the Gunderson car in the RTR line it was heavily upgraded with etched running boards, new trucks with metal wheels, new brake details and fine stirrups and end ladders. When you put the RTR model next to the original MDC model the difference was obvious.

Original MDC Roundhouse model (left) compared to an upgraded MDC model (right)

Athearn RTR model (left) compared to upgraded MDC Roundhouse model (right)

Rather than dispose of these older MDC models I decided to try upgrading them. Again, Plano Model Products came to the rescue with their etched running boards. Changing out the molded plastic running boards for the etched stainless steel part from Plano is the easiest thing you can do to improve the model. Unlike the Accurail model there's no carving or filing or sanding required, though you will have to fill in the holes where the original running board attached to the model. The Plano running board kits include brass supports that you bend and install on the model. The running boards can be installed later if you choose to paint the carbody but leave the running boards unpainted. The prototypes I'm modeling had the running boards painted the same as the carbody so I installed them before painting.

The stirrups can be replaced with A-line's Style B metal stirrups, but I decided to make some using 0.019" flat wire. Once the stirrups were bent to shape I drilled them for 0.012" brass wire pins and soldered them in place. The pins double as bolt heads visible where the stirrup mounts to the carbody.

Like the Accurail cars, I decided to replace all the cast-on ladder rungs with Plastruct 0.010" styrene rod. The grabs were replaced with Detail Associates parts on the first of these upgrade projects before I switched over to BLMA drop grabs. Since that time BLMA was purchased by Atlas, so I'm not sure if they are available anymore, but the point is moot since Tangent drop grabs are readily available and every bit as nice as the BLMA parts.

If you look at the sides of this model you can see I've removed two of the ribs creating a 5-4-5 rib pattern on the carbody side. This represents the predecessor to the Gunderson 4700, the 4692. The model pictured above was decorated as C&S 458927:

Still missing a brakewheel!

Besides the upgraded running boards and ladder rungs, I replaced the trucks and added some weight. I also plumbed the brake components with 0.012" brass wire and added some brake levers on the otherwise bare A end using the Athearn RTR model as a guide.

The model in red still isn't finished.... But when I finally get going on it again it will become BN 456438, a car I've managed to photograph twice:

BN 456438 in fresh paint on the right, Bottineau, ND July 1991

BN 456438 looking a little worn in Saginaw, TX May 2006

When Athearn finally offered these models upgraded in their RTR line, the plain green scheme wasn't available. Not being one to wait around for them to do it for me I repainted one myself:

I'm glad Athearn chose to take these cars to the next level. I've purchased several of the RTR models since. But I'm also glad they gave me a target to aim for as I tried to bring the older MDC Roundhouse version up to date. With a little work, these older models blend in quite well with the superdetailed models from Tangent, Scale Trains, ExactRail and Athearn Genesis.

Carbon Black Hoppers

A few years ago I posted a blog covering Thrall 5750cf carbon black hoppers. At the time I had completed CAD drawings of all the variations on the Granuflator-equipped Thrall car from 1968 to the 1979 version that was built into the 90s. I designed the CAD files so that the car could be 3D printed as a flat kit with details added by the modeler. No doubt it would have been an expensive kit to print, not to mention expensive to procure all the detail parts, then assemble the model and apply paint and decals.

So I was relieved when Scale Trains announced they'd be producing the 5750cf carbon black car in the 1977 version and the 1979 version. I was hopeful they'd tool up body variations to offer some of the earlier cars, but that didn't happen. Since these are by far the most common carbon black hopper I was used to seeing I ordered six. I figured I probably spent as much on those six as I would have on two of my 3D printed kits.

Scale Trains also announced a Thrall 4727cf carbon black hopper at the same time. Unfortunately for me, this car represented a mid 90s prototype. But I wondered if it might be possible to backdate this model to the 1974 version. Of all the carbon black hoppers Thrall built in the 70s and 80s, this one actually looked like a covered hopper instead of a boxcar.

With six of the boxcar-like covered hoppers in my hands I had the makings of a substantial fleet for the carbon black producers and customers off either end of my dream layout. I have to hand it to Scale Trains, these cars are exquisite. I don't think I could have done as nice a job with my 3D printed kits no matter how much I was willing to spend.

But the uniformity of these six cars got me thinking about some of the ACF built carbon black cars the late Wade Griffis had built. He offered decals through his Black Swamp Shops and had a kitbashed or scratchbuilt models to show off each of the decal sets he designed. He was really a pioneer and his models were quite good. I'd looked over these models a dozen times or more and figured I'd build one of each someday.

Back in April someday finally arrived. I figured while I was at it I'd take a crack at a modernized version of the old Rail Shop ACF 3000cf carbon black hopper. And for good measure I bought one of the Scale Trains Thrall 4727 hoppers to backdate. So if six was a good sized fleet, four more new carbon black cars would be even better.

First up was the Rail Shop car. This model began as an ACF 3000cf carbon black hopper. The prototypes were built between 1933 and 1949. In the 1960s many of the cars were enlarged to 4000cf by raising the roof 28 inches. The modification also included replacing the staff handbrake with a horizontal brake mechanism, partial removal of the A end side ladder and replacement of the wooden running boards.

The kit was built per the instructions with a few exceptions. To replicate the taller prototype, the sides were cut along the base of the riveted zee at the top of the side stakes. New side extensions were built from styrene sheet and strip. Likewise the ends were cut and extensions were added. Brake gear components were replaced with Moloco parts, other than the brake cylinder/lever part, which is from the kit. The trucks were replaced with some from a Proto2000 gondola kit. A placard was added to each side to display the Columbian Carbon logo. A Plano running board was installed along with a platform below the handbrake. I lettered the model with Wade's Black Swamp Shops decals. I ended up replacing the kit's outlet gates with some 3D printed gates and covers I made, but these aren't shown in the photos.

Next up was the Scale Trains 4727cf hopper. I removed the side stakes using a Dremel tool, a chisel, then finer and finer grit sanding sticks. The roof and hatches were replaced with a 3D printed part adapted from my original Thrall 5750cf CAD file redesigned to fit the Scale Trains model and reuse the etched running board. I built up new side stakes from tee and strip styrene to create the columns used by Thrall in the early 70s. Once again I used some of Wade's decals, though the decals were intended for a model of a 5750cf car.

Continuing the trend of ramping up the difficulty of the build, I took on an early ACF 4589cf car. The prototype is a Plate C car, so I started with a 1970 and earlier Atlas ACF 4650cf hopper. The length is pretty close with the Atlas car being just a little too long, but not long enough to jump out. The slope sheets on the 4589 are closer to the rail making the vertical portions of the car ends taller. I chose to live with the difference on this model but in the future I may start with a car that's a better match for the ends. One unique feature of the early high-handbrake 4589 is the area behind the tall side ladder. It's recessed to allow some space behind the ladder rungs. The holes on the roof were plugged and new 3D printed hatches were installed. This car received new Kato 70-ton trucks. Black paint and Black Swamp Shops decals set no. 104 were applied.

Finally, I kitbashed an ACF 3390cf carbon black hopper from the Atlas 3-bay cylindrical hopper. Again the first step was to plug the roof holes and blend the plugs into the roof contour. Next I filled in the seams in the body and primed it. The entire car was shortened by four scale feet with a single section taken from the middle of the body and two two-foot sections taken from the underframe between the bays in order to obtain 12-foot hopper outlet spacing. I added new 3D printed hopper outlets, modified the end cages and installed the Plano running board set. The trucks were replaced with Exactrail 70-ton trucks and the roof hatches with some parts from an Athearn ACF 5250cf covered hopper I had originally intended to use for this model. Again, Black Swamp Shops decals were used.