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.

GP60 Demonstrator EMD 7

When EMD introduced their four axle 60 series to the world, they did it with six demonstrator locomotives painted in the attractive blue and white scheme worn by the SD60 demonstrators and later the Oakway SD60 lease fleet. The three GP59 and three GP60 locomotives had another feature not seen since the GP30: an aerodynamic cab with a pointed cab face. The hood corner radius of the nose was increased from the standard 4" to 9" and the standard 4" radius was applied to the leading edges of the cab. The effect of the streamlining was a striking appearance, accentuated by the color scheme.

The demonstrators made their way across the Santa Fe and Southern Pacific systems among others. In an attempt to make the locomotives ready to serve any railroad they were equipped with many of the options specified by different railroads, including a variety of different fuel fillers, extended range dynamic braking, a cab air conditioner, auxiliary warning headlights and a UDE light.

The extended range dynamic braking hatch was larger than on previous models and protruded about a foot from the hood sides. The rounded edges and sloped faces of the streamlined cab were continued to the dynamic hatch. Although none of the railroads that purchased production GP59s or GP60s opted for the streamlined cab, all were equipped with the large dynamic hatch. Eventually the streamlined styling of the hatch was discarded for a much simpler to fabricate version with squared edges and flat faces. No production GP59s received the streamlined dynamic hatch, but ATSf 400-4019, SP 9600-9619 and SSW 9621-9634 were so equipped. All others had the later, angled hatch.

After the demonstrators made their case for EMD to the prospective railroads, the GP59s were sold to Norfolk Southern and the GP60s were on a long term lease with Southern Pacific. Eventually the GP60s were returned to the lessor, sold to another lessor, then finally sold to CSX as their 6897-6899.

I modeled one of the demonstrators by drawing the hatch and the cab/nose combo in AutoCAD, then 3D printing the model through Shapeways. I applied the parts to a factory painted Life-Like Proto2000 GP60 model. I had to shorten the fuel tank at the rear to better match the prototype, but otherwise I just painted and decaled the new parts to match the factory paint, added a few fuel tank details, a new horn, and some cab mirrors.

I sell these parts on Shapeways, along with many others, and one of the modelers who purchased these parts noticed an error in the dynamic hatch with the size of the exhaust. Wouldn't you know it, I transposed some numbers while drawing the part. I have since revised the dynamic hatch, but at this point I have not replaced it on the model. Thanks to Roderick Quebral for his keen eye and help with this hatch and the SD40-2 hatches I drew in recent months.

SP B36-7 7766

So while I was working on the Cotton Belt B30-7 I decided to reuse the original cab to build another Southern Pacific locomotive. At the time I was just beginning to learn about the evolution of GE diesels in the Dash 7 series. Michael Eby covers four-axle Dash 7 phases on his website Trainiax. According to Trainiax, the overall length of the locomotive changed from 62'-2" to 61'-2". The difference could be seen in the position of the stepwells relative to the end of the short hood and the long hood.

Truck centers are another detail that changed throughout production. This was a trend that continued through early Dash 8 production as the series was developed. I don't have the ability to cut up or mill diecast frames and I certainly don't have the ability to put them back together. Well, not square anyway. What I can do is design and print a new frame.

I would love to be able to print in metal, and several metal materials are available through Shapeways, but size, cost and printing tolerances make it impossible at this time. Maybe later. Instead, I printed the frame in Shapeways' White Strong and Flexible nylon. It's a pretty strong material if the walls are designed thick enough. Detail isn't much of an option with this nylon material, so I designed it to accept an Atlas B30-7 fuel tank. Unfortunately, when I placed my parts order with Atlas these were unavailable. Back to the computer to design and print a fuel tank. I also worked up some new air reservoirs for another project.

In light of the difficulty I had obtaining an Atlas fuel tank, I figured I'd design the frame to accept Athearn trucks and drive shafts. I have a few trucks on hand already and the drive shafts come in a variety of lengths. The only trouble is the Smokey Valley sideframes are terrible. Atlas FB-2 sideframes from the original Kato/Atlas U23B aren't that great either, but they are better. The current Atlas B23-7/B30-7 sideframes look much better. At some point I'm going to have to come up with a version of the frame that accepts Atlas trucks. For now, I'm going with the tolerable Smokey Valley sideframes. Here are a couple shots of the frame:





To construct the B36-7 shell I simply cut down an Atlas C30-7 shell removing a portion of the auxiliary cab behind the operator cab and toilet compartment (the area between the second batten strip behind the cab and including the third batten strip from the front). I replaced the exhaust with a Hi-Tech part and added the gyralight/UDE light mount on the rear. I also added some Hi-Tech grilles to the radiator doors and scratchbuilt a cabinet to place behind the conductor's rear window on the walkway.

The sill is an Atlas part cut down and shortened at the stepwells. The door under the walkway on the conductor's front corner of the cab was replaced with one made from styrene to match the other doors. The modified C30-7 shell and nose were glued to the shell since the mounts for the B30-7 sill and C30-7 aren't compatible. The cab is removable at this point. Speaking of the cab, even though the front windows were correct for the B36-7, the locomotive was delivered without the auxiliary windows so those had to be filled in. I used Bondo spot glazing to do the job. After painting the cab I could see some shrinkage around the window perimeter. I went back and filled them in again and touched up the paint.















I still have more work to do, including the handrails. I was able to keep the end railings, but with the shorter overall length it's not possible to reuse the Atlas side rails. I'll make new ones from Utah Pacific stanchions and brass wire.

This project started off with a cab. The GE Universal series/Dash 7 series cab became something of an obsession for me throughout the second half of 2017. More later.

Cotton Belt EV Caboose 41

The previous post covered the other "test" caboose I built when I began developing the concept of a 3D printed modular caboose kit. The prototype for this model was the inspiration for the whole caboose project. Like some standard cupola cabooses of Norfolk & Western and Great Northern, Cotton Belt's extended vision cabooses had the cupola side windows placed at the corners. Although it is possible to modify an Atlas caboose to represent this unique variation, I decided instead to try my hand at 3D printing a replacement cupola.

With the memory of kitbashes of a Frisco extended vision caboose:

...and one of Mopac's distinctive extended vision cabooses fresh in my mind:

...it wasn't long before I decided to print a new roof, ends and sides to save myself the trouble of cutting up the Atlas model. And so began - innocently enough - what has become a quest to be able to model nearly any version of the International Car Company's extended vision caboose.

Since the process was described in the previous post, I will let the photos do the talking here for the most part.

This was the first cupola I designed for this caboose. It has an opaque, white appearance that is the result of washing it in isopropyl alcohol to remove the waxy residue that's part of the printing process. Unfortunately, the alcohol also had the effect of distorting and shrinking the part. I also discovered that the alcohol made the part brittle at the same time I discovered the shrinkage. When I tried to fit the cupola to the modified Atlas body it split the cuopla. I printed another version of this cupola design and that's what you see on the model. 

After experiencing an alignment issue between the cupola and the printed body (which occurred because I didn't include any keys or tabs so the interior would remain clean for detailing), I revised the early higher cupola design to eliminate the sidewall extensions originally designed for the Atlas body and incorporated the additional body height into the sides. This design change means the higher cupola cannot be easily modeled using the Atlas caboose without modifying the body to include the side extensions, but it really isn't a difficult problem to solve for the motivated modeler. I couldn't see why my design needed to suffer to accomodate the Atlas body when I had no intention of using it for future builds. This change was carried out through all affected models in my product line. If you look closely, you can see the area underneath the cupola where I had to use Bondo to fill in the misaligned areas between the cupola side extensions and the sides.

I painted this model with a brown paint mixture I tried to match to an Athearn Genesis caboose. I started with Model Master Rust and mixed in some burnt umber and burnt sienna until I was satisfied/gave up. The orange ends were much easier: they are Model Master Go Mango. The window frames were painted the same as on the Santa Fe caboose. 

Just as with the Santa Fe model, I'm happy with this one. I would like to see the printing process get a little better and cheaper, but in the end I got much more than I had hoped for when I originally dreamed up the idea of printing rather than kitbashing this model's cupola. 

Highball!