Dumps, Pups, Flat-decks, Ragtops, Gensets, Chassis and Cans

Ah, vehicle models! The unsung heroes of the model railroad landscape. The supporting cast backing the stars of the show. As scenery or even loads these models seem to get far less attention. Let's face it: most modelers are willing to let anachronisms, detail inaccuracies, and even a lack of detail go just to have a reasonably close version of a particular vehicle model.

There are some who look at the vehicle models as the real stars and the trains are just the backdrop to the action on the highway. In other scales these modelers tend to be separate from the railroad modelers; only in HO scale would these folks be considered a subset of the larger model railroad hobby. But there are many who push the limits and take HO scale vehicle modeling to the forefront.

For me the Athearn Freightliner cabover kit was a great introduction to HO scale vehicle modeling. It was very cheap compared to the giant 1/25 scale models and though it was a simple model it was proportioned beautifully. I remember clearly the first time I saw Leonard Frere's models in the HO Model Railroading Handbook:

The heritage of that daycab Freightliner straight truck and trailer was obvious: Athearn's tractor and Fruehauf reefer van models. The creativity behind this kitbash started me off on a path of bashing my own models as a teenager. To this day it almost depends on which way the wind blows whether I'd consider myself a railroad modeler first and a vehicle modeler second or vice versa. For the past few months it's been decidedly skewed toward vehicle models.

Dumps

At the inaugural Texas Railway Modeling & Historical Society prototype modeler's meet in June 2021 I got to meet a bunch of local model railroaders of the same stripe as me: guys who not only count rivets but measure them, people who are experts in their field of interest, folks who design and build and paint and print their creations. 

I met Marshall of MP Scale Models who had several N scale models displayed that he 3D printed. These were resin prints that were so much smoother and more finely detailed than the acrylic prints I'd been getting from Shapeways. It turns out he lives close by and we have some common interests in prototypes that bridged the divide in scale. Soon the conversation turned to printing my designs and he felt confident he could print the trailers I asked about. A few weeks later he handed me this:

1979 Fruehauf 32' Dump Trailer kit fresh off the printer

I took this photo as soon as Marshall put it in my hands. I could already tell the material was so much smoother than what I could get from Shapeways. The extended hydraulic ram was straight and the wheels looked amazing.

It didn't take long before I had the parts primed and assembled. Here it is in the raised position then with the hydraulic rams swapped out in the highway position.

 

A similar truck and dump trailer at Flynn Yard in Oklahoma City

Although these aren't cheap to print, Marshall was able to give me a much better price than I could from Shapeways. And the quality difference is just ridiculous, truly on another level. These prints are gorgeous! 

Shortly after I printed these first samples I found the elusive 39' version of this dump trailer for sale on an auction site. The photos weren't great but they were good enough for me to count the ribs and confirm that lengthening the trailer would be a simple slice and dice. In no time I modified the CAD file to model the longer version of this kit. 

When I wrote the instructions for the dump trailer kit it occurred to me many modelers will want to assemble the model with the bed lowered in the highway position and won't want to go to the trouble to make the model positionable with interchangeable hydraulic rams (sorry, I can't get those to operate!). So, to speed up the assembly of trailers that will only ever be in the highway position I came up with a variant that is printed in six parts: four tire/wheel parts, one spring suspension part and one "everything else" body part:

The "one-piece" 39' trailer model with unpainted tires

Pups

After this success I had to try a few other ideas out, and none was more exciting to me than the bullnose pup trailer. When I first drew these and uploaded them to Shapeways I was so excited. But then I saw the price. Outrageously expensive! Unfortunately it was to the point where I could maybe have one or two, but a warehouse dock full of them? No way. 

The worst part was I'd made a few mistakes in that first draft and the model needed to be repaired manually. I fixed the wheel wells and the position of the rear axle but I couldn't do much for the fact that it's a scale foot too short. Ouch. Here's the first Shapeways print with my custom decals printed by FedEx Office 😮😁 and the revised version printed by Marshall below:

3D printed flat kit from Shapeways, warts and all

First print from MP Scale Models

The basic bullnose trailer drawing was based on a wedge pup built by Trailmobile, but with a few minor changes it could fit in with prototypes built by Road Systems, Strick and Evans Monon among others. Motor carriers who operated these bullnose trailers include: Transcon, Pacific-Intermountain-Express (and successors Ryder/P-I-E and P-I-E Nationwide), ANR through Garrett Freightlines and Graves Truck Lines, Brown Transport, Consolidated Freightways, Roadway Express and Santa Fe's SFTT. 

Naturally there were differences between the versions each of these carriers had and for those with larger fleets there were even differences within the fleet. So it wasn't long before I found myself cataloging these options of noses, sides, wheel well cutouts, doors, pintle hooks, taillights, suspension and landing gear. I figured the easiest way to break these variations down was to print the doors and floors separate from the body, that way those parts could be combined with each other to form unique models.

The basic kit

Here are some examples of variations on the printed models:

I was talking with my friend Bob of Masterbilt Models about the possibilities with these variations, how it reminded me of when I'd take the girls to the mall and they'd come home with a stuffed animal they chose and helped make. A modeler could select a door, a floor, the body and the type of wheels for a trailer they wanted to model. The idea for Build-A-Pup was born.

This same idea can be extrapolated to other trailer designs and I've got a few in the works. Fruehauf trailers have always been fascinating to me since I was a kid building 1/25 scale models. Those AMT kits seemed to have every variation Fruehauf made covered in model form back in the 70s and 80s, so it didn't take long to become familiar with those details that made a Fruehauf trailer stand out. After drawing up so many bullnose pups I moved on to drawing Fruehauf wedge and straight-floor pups. I've only just printed out two examples, but like the Trailmobile pups the possibilities are practically endless.

All done except for the wheels

The Roadway trailer is 102" wide and it's the first one of the wedge trailers I've widened from the 96" wide CAD file. After applying the Microscale decals and seeing the columns of rivets relative to the lettering the mistakes I made cutting and splicing the CAD file are obvious. That's always how it goes!

The Central trailer represents a prototype cut down from a 40' x 96" Z-van trailer for P&D service. Bob had the Central decals made and they look fantastic.

Flat-decks and Ragtops

This brings me to flat deck trailers. Thinking back to those AMT kits there were some really cool flats including one that telescoped into a long version for oversize loads. While searching for photos of those online I stumbled across some more straightforward Fruehauf designs. The basic trailer is the same but the suspension setup can be changed from a fixed spread to a sliding tandem. Fruehauf used modular suspension components to build up both their fixed spread and sliding tandems so once I had the components drawn I started "assembling" them. The shape of the components changed over time from an early triangular shape to the later spade shape. 

Late sliding suspension 

Early fixed spread suspension 

Another project I just had to take on was a staple in the TOFC fleets of old: the ragtop van. Again, the Fruehauf version was a no-brainer for me since I'd drawn the body elements for the Fruehauf pups and the frame and suspension parts for the flats. This one is crying out for Santa Fe or Rock Island decals:

Gensets, Chassis and Cans

Speaking of decals (and realistically this deserves its own post so I'll work on that), I was all set to order some decals for these trailers and some other vehicle details last year. I had begun putting together a package illustrating the details I wanted captured in the artwork and some examples of the fonts and things that would be needed to complete the artwork. While describing this project to Marshall he suggested I try to create the artwork myself in Inkscape, a free vector software, that way I could get the details I wanted without having to iterate the design with a third party (in other words, save some dough!). 

So I downloaded Inkscape and started watching some tutorials. In no time at all I had some finished artwork and began working with Bill at PDC to print the decals. So what you see above on the bullnose trailers is the result of that process. I not only was able to create the artwork for the models on my terms and to my specifications, but I also found that I really love drawing decal artwork and creating fonts. Who knew?

Learning how to make decals has opened up some projects I've wanted to do for ages. Honestly, now I have more things on my plate than I ever expected. But that's a good thing. First of all, reefer containers and more importantly, reefer containers filled with tropical fruit. Those little clip-on gensets keep the reefer units powered to keep the containers cool in transit:

These little guys had been on my list for a long time. After finding some repair manuals with isometric drawings I was able to create a CAD file. Decals soon followed.

You can get Con-Cor and Walthers reefer containers lettered for Dole and if you're lucky you can find the Microscale Dole container decal set. Likewise, if you look you can find the Con-Cor container lettered for Chiquita but they are not easy to find. So I decided to correct that problem and make my own Chiquita container decals. 

A few months later and I had created artwork for Dole containers. 

3D printed gensets and some Chiquita containers with custom decals

But that wasn't enough, because Dole containers typically move on Dole's own Fruehauf chassis with gensets mounted below deck, so of course I had to draw the gensets...

...then the Fruehauf chassis...

...and finally a Fruehauf standard height reefer container:

This one will be much closer to the real thing than my stand-in made from an American Limited chassis with printed genset and fuel tank and a Walthers hi-cube reefer container:

Going back in time a little bit, around the time I printed the Fruehauf dump trailer, I had also printed this Gindy container chassis, based on photos posted by Ed Sutorik. This chassis helps add a little variety to the fleet with something that's appropriate for the 70s through the 80s. It doesn't hurt that they're fairly inexpensive to print, too.

3D printed Gindy chassis in foreground, American Limited chassis in background

Gindy chassis, Walthers container and ThermoKing clip-on genset

The Gindy chassis and the Fruehauf chassis share some of the same bones, but there are some real differences throughout. It's the same with the bullnose trailers and the other pup trailers. Those little differences really make the difference. The takeaway is that I can dial in any variation I want to draw and I can print it. 

Any variation? Why not? 

Well, it's actually kind of the opposite problem manufacturers have when they cut tooling. They are trying to find the most common variants to model so that the tooling can be used across a variety of paint schemes. Many times little compromises have to be made, such as the double row of rivets on this prototype can't be modeled or the different step wells on that model can't be done. 

With manufacturing on demand that's not a problem. But where it starts to get out of hand is having dozens and dozens of variations. Chasing down every esoteric detail, defining them and describing them on a model-by-model basis might be asking a bit much. In the case of these containers, chassis and trailers, some things just have to be let go or the project will never end. It truly can spiral out of control.

I can't help but feel optimistic about this endeavor. It's easy to say the possibilities are endless with 3D printing, but... And there's always a "...but" in these discussions. But for an aspiring cottage industry manufacturer -- today's equivalent of yesterday's one-man resin casting shop -- the technology is finally good enough. Even inexpensive hobby printers can achieve a resolution fine enough to satisfy the most discerning modelers. In not much more time 3D printers will achieve the same or better resolution than expensive injection-molded plastic. 

Another great aspect to manufacturing on demand is the democratizing effect it has. Twenty years ago an aspiring designer had to apprentice as a toolmaker and either be well off himself or be backed by some deep pockets. That's not true anymore. It's possible to design sophisticated models using free software or even old software (ahem, looking at you AutoCAD) on mediocre computers. You don't even have to own a printer -- I'm living proof of that -- but besides those entrepreneurs doing contract printing many libraries have printers available to the public. You don't need an engineering or design background to design 3D models, either. Anyone motivated enough with some basic resources can do it. Like Chef Gusteau says, "anyone can cook!" 

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.