Railroad Forums 

  • First HO Hyundai-Rotem CEM bi-level cars

  • Discussion related to everything about model railroading, from layout design and planning, to reviews of related model tools and equipment. Discussion includes O, S, HO, N and Z, as well as narrow gauge topics. Also includes discussion of traditional "toy train" and "collector" topics such as Lionel, American Flyer, Marx, and others. Also includes discussion of outdoor garden railways and live steamers.
Discussion related to everything about model railroading, from layout design and planning, to reviews of related model tools and equipment. Discussion includes O, S, HO, N and Z, as well as narrow gauge topics. Also includes discussion of traditional "toy train" and "collector" topics such as Lionel, American Flyer, Marx, and others. Also includes discussion of outdoor garden railways and live steamers.

Moderators: 3rdrail, stilson4283, Otto Vondrak

 #1205101  by Kurt-Trirail
 
They're not in my hands just yet, but thanks to a bit of work in Adobe Illustrator, and some assistance from a gentleman who does styrene milling, the very first HO-scale replicas of Hyundai-Rotem's CEM bi-levels now exist:

Image

Should be an interesting build. I'm using spare Athearn Bombardier chassis as the base, and I designed the sides to work with Train Ready Products (formerly Train Station Products) core kit roofs.

Near as I can figure it, I'm pretty much stuck using 3D printing for the ends. Not sure I care to go through the effort of resin casting the 3D prints either. At any rate, it'll be an interesting venture.

-Kurt
 #1205189  by Desertdweller
 
Kurt,

Your HO car sides look very good.

I do not model in HO. I model in N scale, 1950's-1960's passenger operations specifically.

It seems to me that this process may be used to make affordable cars not normally available commercially. Especially types not widely used, but confined to one or two railroads, thus not having enough demand for injection molds.

Types that come to mind are Budd baggage-tavern cars like were used on the CB&Q and Rock Island. Or parlor-dome-observation cars as used on CB&Q and Wabash. Or SP 3/4 length domes. Or the low-profile P/S dome cars used by B&O, C&O, ACL, D&RGW.

Les
 #1205193  by Kurt-Trirail
 
Desertdweller wrote:Kurt,

Your HO car sides look very good.

I do not model in HO. I model in N scale, 1950's-1960's passenger operations specifically.

It seems to me that this process may be used to make affordable cars not normally available commercially. Especially types not widely used, but confined to one or two railroads, thus not having enough demand for injection molds.

Types that come to mind are Budd baggage-tavern cars like were used on the CB&Q and Rock Island. Or parlor-dome-observation cars as used on CB&Q and Wabash. Or SP 3/4 length domes. Or the low-profile P/S dome cars used by B&O, C&O, ACL, D&RGW.

Les
The process is conducive to it, though I'd tend to believe that laser cutting ABS would be a better method for the small details of N-scale. That is, of course, provided core kits are available in N. Train Ready Products (AKA Train Station Products) has been making HO core kits for years now, and Brass Car Sides has been making (surprise) brass car sides to work with the TSP kits for quite a while - I take it there is nothing similar in N-scale?

-Kurt
 #1205409  by Desertdweller
 
Brass Car Sides make some sides for smooth-side passenger cars (GN and MILW, mostly). There was a company making core kits, but searching for this, it seems they are experiencing production difficulties.

The problem seems to be that the cost of the brass sides, coupled with the need for a donor core, makes a fairly expensive car that still needs to be primed and painted and decaled. If the plastic car sides can be produced at a much lower cost than the brass, especially using 3-D printing, the cost differential may make producing these practical. It would be a risk, but expanded products could help offset the cost of the 3-D Printer.

Production of the curved corner glazing of the Budd domes may be a problem. Maybe a vac-formed clear insert in the dome would solve this.

It looks to me like the initial cost of the 3-D printer would be the big capital outlay. Once you have bought the printer, the more different salable products you can produce with it the better. The big advantage over injection molding would be the lower cost of CAD designs, which would never wear out as opposed to metal molds.

The 3-D printer could also be used to produce car interiors.

The Rowa line of corrugated passenger cars that Con-Cor sold would be a likely good seller in N-scale. I have heard the molds for these cars were destroyed. If an original set of these cars were obtained for patterns, 3-D printing may be a good way of getting these popular cars back on the market.

Les
 #1205420  by Mike@IHP
 
Lookin' good, Kurt! :-D

3D printing can be used for just about anything you need for static modeling, and scaling for other scales is easy. It's especially suited for those one-off or one-time projects. There's just the CAD time cost for the CAD designer, really, then your parts cost. Consider 3D ends for these, and even roofs if you can't get the core kits anymore. Remember, my CAD skills are at your disposal!

Mike Bartel
IHP
http://ihphobby.tripod.com" onclick="window.open(this.href);return false;
http://www.shapeways.com/shops/ihphobby" onclick="window.open(this.href);return false;
 #1205487  by Kurt-Trirail
 
Mike@IHP wrote:Consider 3D ends for these, and even roofs if you can't get the core kits anymore. Remember, my CAD skills are at your disposal!
Interesting you should mention CAD skills. Though I do not have a multi-purpose 3D program, I have been tinkering (I'm held up due to a lack of any photographs of the roof or rear carbody) with a BL36PH in Train Sim Modeler (top is w/o polygon smoothing, bottom is w/poly smoothing) modeled directly off the Brookville blueprints of the production model (not the early prototype images sans-raised roof):

Image

Though TSM is limited in its export functions, the file can be back-converted into .3DS for import into any number of other 3D programs; enough so that a printable model is possible - Thomas Pearce of BLLW and I tried the import/export once before to success. I've tinkered with Blender as well, and should be able to get a foothold on the program if I work with it some more.

That said, I'm not quite sure how 3D printing resolves the polygon stepping as on the nose of this model, or whether it would require further refinement for printing.

Nevertheless, send me an email about those car ends, Mike. Also let me know if the BL36PH model would of interest, for I'd have no problem handing the 3D production of it to you, if it would be of interest to IHP's Shapeways customers. At least I'd be assured to have one in my roster that way.

-Kurt
 #1205491  by Desertdweller
 
It seems to me that 3-D printing would be much cheaper for small production runs than injection molding. I haven't compared actual prices, but I'd bet a 3-D printer is much cheaper than an injection molding machine. Plus, it is small enough that parts can be produced at home. The CAD programs take the place of the injection molds and never wear out.

There is also a lot of waste involved in injection molding. Much of the resin is used in producing gates and sprues. Any voids not filled in the molds will create unusable parts. As molds wear, they can develop gaps between the mold halves causing flash. If the mold haves wear so they do not line up perfectly the parts will have a "jog" in the middle of them. Large parts are prone to warping as they cool.

The waste can be reground and reshot, but every time this is done, the quality of the plastic degrades.

An injection molding machine is the size of a small printing press and can weigh several thousand pounds. It also requires a lot of energy, and works on high pressure and temperatures. It is no wonder low-production injection-molded parts are expensive.

If I understand the 3-D process correctly, the parts are produced with little waste, are totally repeatable, and can be modified in production by tweaking the software. A library of CAD programs could take the place of millions of dollars of injection molds. Sounds like a perfect fit for the hobby.

Would it be possible to get around the need for core car kits or donor cars by producing car floors, ends, and interiors by 3-D printing, too? Then complete car kits could be marketed. The buyer would only have to add trucks and couplers, weights, and paint. Back in "the day", model train cars were assembled from stamped brass sides with milled wood floors, roofs, and ends. It could lead to a case of "what's old is new" and maybe encourage a new round of building verses buying pre-built, pre-finished cars.

We should remember that it hobby started as a low-cost, do-it-yourself craftsmens' hobby. People could build their trains on their home workbench (anybody still remember those?) to learn and keep sharp on their fabricating skills during the Great Depression. If the economy goes down the toilet again (I think it will), there could be a big demand for that type of hobby again.

Les
 #1205494  by Kurt-Trirail
 
Desertdweller wrote:If the plastic car sides can be produced at a much lower cost than the brass, especially using 3-D printing, the cost differential may make producing these practical. It would be a risk, but expanded products could help offset the cost of the 3-D Printer.
If a corrugated-side car, I can see where 3D printing would work in N-scale. Laser-cut sides would probably work for smoothside/UP style cars.

-Kurt
 #1205499  by Mike@IHP
 
Desertdweller wrote:It seems to me that 3-D printing would be much cheaper for small production runs than injection molding. I haven't compared actual prices, but I'd bet a 3-D printer is much cheaper than an injection molding machine. Plus, it is small enough that parts can be produced at home. The CAD programs take the place of the injection molds and never wear out.

There is also a lot of waste involved in injection molding. Much of the resin is used in producing gates and sprues. Any voids not filled in the molds will create unusable parts. As molds wear, they can develop gaps between the mold halves causing flash. If the mold haves wear so they do not line up perfectly the parts will have a "jog" in the middle of them. Large parts are prone to warping as they cool.

The waste can be reground and reshot, but every time this is done, the quality of the plastic degrades.

An injection molding machine is the size of a small printing press and can weigh several thousand pounds. It also requires a lot of energy, and works on high pressure and temperatures. It is no wonder low-production injection-molded parts are expensive.

If I understand the 3-D process correctly, the parts are produced with little waste, are totally repeatable, and can be modified in production by tweaking the software. A library of CAD programs could take the place of millions of dollars of injection molds. Sounds like a perfect fit for the hobby.

Would it be possible to get around the need for core car kits or donor cars by producing car floors, ends, and interiors by 3-D printing, too? Then complete car kits could be marketed. The buyer would only have to add trucks and couplers, weights, and paint. Back in "the day", model train cars were assembled from stamped brass sides with milled wood floors, roofs, and ends. It could lead to a case of "what's old is new" and maybe encourage a new round of building verses buying pre-built, pre-finished cars.

We should remember that it hobby started as a low-cost, do-it-yourself craftsmens' hobby. People could build their trains on their home workbench (anybody still remember those?) to learn and keep sharp on their fabricating skills during the Great Depression. If the economy goes down the toilet again (I think it will), there could be a big demand for that type of hobby again.

Les
Hi Les and all,

3D printing is wonderful and will revolutionize personal modeling, but it's not for short commercial production runs, nor is it desirable to consider purchasing a 3D printer for your home modeling right now.

Yes, there is no tooling or waste (unless you print many samples until you get it right) and it's much better than resin casting for multiple parts for personal modeling, but the cost does NOT go down for multiple parts. I've investigated doing 'bulk' printing by several 3D printing services and they all tell me that the price doesn't go down appreciably, if at all. They all cost the same to print. So, production runs, even small ones, aren't practical yet. Maybe if your part was very small (I've seen it done for 1:700 scale carrier aircraft), but that doesn't apply to many usable parts for modeling at this point, I think. If you need a lot of parts for your own modelmaking, you can have them done in bulk, but be prepared to pay the same price for one or one hundred.

If you are considering purchasing a 3D printer for your own use, you have to get the best one for model part making, and those start at US$20,000 for the small ones. There are some that are less expensive that rumor to be a few thousand, but those DON'T do model railroad-quality parts. Not even close. You want the best quality you can get and that costs money. You can't be cheap about model part making. If you only intend to make a few pieces over time, then your best bet as a modeler is to have the CAD work done somehow, then use one of the online printing services to make your parts on demand. It's a lot cheaper over time than owning your own machine, and much easier. You don't have to maintain the machine or buy the materials for it. Buying a 3D printer is NOT like choosing a laser printer for your computer. I am discussing working with a fellow who wants to purchase a 3D printer to do 3D printing as a general service as well as for patterns for his own model railroad range (narrow gauge stuff), and even he is being very cautious about it because he knows he and his business partner will need the business beyond me to really get their money's worth from it. If someone who wants to do it professionally as a service is thinking this way, then you as a personal modeler probably shouldn't be at all. I considered a 3D printer for IHP, but I found it to be easier and more cost effective to utilize the online printing services.

Why do car sides when you can do a whole body? We don't have to think in these old terms anymore. One-piece bodies and variations in 3D are as easy as a few clicks of the mouse. N scale carbodies don't cost that much to 3D print (check out the ones on the IHP Shapeways page to get an idea). Why make it more difficult? That's the point of technology; it was supposed to make our lives easier! :-)

Kurt, I'd be happy to help with any 3D design or advice or marketing. You seem to have a good start on that loco model. I think there were drawings of those locos in MR or RMC a few years ago. I might still have them if you need them.

Thanks!

Mike Bartel
IHP
http://ihphobby.tripod.com" onclick="window.open(this.href);return false;
http://www.shapeways.com/shops/ihphobby" onclick="window.open(this.href);return false;
 #1205518  by Desertdweller
 
Mike,

If the good 3-D printers are too expensive for home use or for low-production commercial use, that pretty well eliminates them as a hobbyist tool. I guess if a person were to buy one of these, he would have to go into the on-line 3-D printing business to make it affordable. You can still build a pretty nice model railroad for $20,000, although I'm sure many of them cost much more than that.

I'm concerned that the shift from a build-it-yourself hobby to a ready-to-run hobby will have a negative impact on its ability to survive hard times. Even easy to assemble kits that require finishing give more hobby value than complete off-the-shelf models.

There are still many high-quality plastic passenger cars in N-scale that can be had for $20 each if purchased in 10-12 car sets. Figure closer to $30 each if purchased individually.

I have a number of these cars, but I generally weather them lightly and paint the interiors.

I have worked in the plastic industry as well as the railroad industry. Injection-molded molded models can be produced to sell at a reasonable price if the economy of scale is involved. This is what companies like Walther's and Con-Cor have done. Pick a reasonably generic design (not hard for streamlined cars, as only 3 companies built them, and tended to base their products on standard designs), and offer the cars in a range of paint liveries. The problem comes when you want to make models of limited, specific prototypes (like Milwaukee Road P/S Superdomes). You either have to sell them in small quantities to satisfy your customers (and chance losing money), or slip them into special "sets" of cars to move them.

Injection-molded parts are cheaper to produce in large production runs because of purchasing resin in bulk and the amortization of production equipment, especially molds. Injection molds have a limited lifespan and need to be reworked or replaced when worn beyond a certain point. 3-D printers and CAD programs could be amortized, too. I don't know anything about the lifespan of a 3-D printer compared to that of an injection molding machine. Surely they eventually wear out. Injection molding machines are very robust, and wear is confined to things like bearings, hoses, and seals. In other words, things that can be replaced with a set of wrenches.

Back in the 1950's, when I began building models, injection-molded plastic models were considered "high-tech". I remember building models with vac-formed styrene parts and others that were cast of metal. Some were kits made of milled wood parts.

There was a certain value to own something you have built and painted. This cannot be equaled by buying someone else's work.

Les
 #1205531  by Desertdweller
 
Mike,

I forgot to say this, but the 3-D printer can be depreciated as capital equipment, too. So in a few years it can "pay for itself" in tax savings. That ought to take a big bite out of cost of production.

The CAD programs would definitely be a business expense, but I don't know if something that does not depreciate (intellectual property) can be depreciated for tax purposes. I doubt it.

Les
 #1205746  by Kurt-Trirail
 
Mike@IHP wrote:Kurt, I'd be happy to help with any 3D design or advice or marketing. You seem to have a good start on that loco model. I think there were drawings of those locos in MR or RMC a few years ago. I might still have them if you need them.
I greatly appreciate it, Mike; I'll send an email soon with a few questions about refining the 3D file. I don't plan on selling copies of the BL36 or the Rotem ends though.

The earliest BL36PH drawings differ significantly from the production locomotive. I was lucky enough to extract an accurate side view from the background image of the Brookville website.

That said, the car sides arrived today. The edges are sharper than I ever imagined:

Image

Image

-Kurt
 #1205958  by Mike@IHP
 
Hi Les,

3D printing really is very much in the future of the hobby, in any case. It won't replace injection moulding anytime soon, but it might just threaten some resin casting in a short while. In addition to eliminating most of our resin kit range and resurrecting some of them in 3D, I myself have ceased scratchbuilding and doing any production work by hand. I'll still build kits for myself, and I'd like to build my dream layout someday, but for many personal projects, I find myself CAD-drawing whatever parts I need and then printing them, whereas before I might be sculpting them out of Evergreen plastic or something else. I'm actually pleased to be done with that.

Problem with depreciation of a 3D printer taking a few years is that the technology is moving so fast and getting better all the time, that your machine will be obsolete long before that. It's like computer and cell phone technology. I really wouldn't recommend buying your own 3D printer right now unless you intend to get into 3D printing itself in a big way. Otherwise, it's best to just use the online services and let them worry about all of the unpleasant stuff. It will allow you to make more stuff for yourself!

Injection moulding and 3D printing are for different purposes. It is still more cost-effective to do a production run in plastic than any other process, chiefly for the reasons you cite (though I might dispute the perception of the costs and prices for railroad models, but that's for another conversation). 3D printing is not for large production runs right now. Small parts, perhaps, but not things like body shells. 3D parts take too long to print and the cost for a typical HO one-piece body shell is between $100 and $400 (depending on the length) in the best process (less any profit you might have to make on it). N scale is a bit cheaper for 3D printing, but I find it's easier to sell N scale bodies and parts directly from a site like Shapeways and forgo the ordering for inventory and tracking of orders, particularly for one-off or limited-interest items. There's a question of the 3D resin material's long-term stability too, but it seems to be fine for most everyday static modeling.

You can use cutting edge technology in your personal modelmaking and still get a tremendous sense of accomplishment. I think Kurt is doing that right now with these bilevel cars. If it were me, I would have done the whole car in 3D, but he found a way to do it within his budget and is using the sides with some available cars and parts to help speed it up and keep things consistent with other models. Kurt decided there was a better way than cutting and sculpting pieces of Evergreen sheet plastic himself. (Obviously, you valued your sanity, Kurt! :-)) We don't have to cede everything to RTR or new technology, nor do we have to give up modeling even in hard times, and there is such tremendous diversity of offering to us to fit all budgets. I personally am not worried about any of that. I've seen some nice models made from cardboard and there are even some nice ranges of models made from cardstock that have big followings. That's what is great about this hobby and I think it will largely continue to be so.

Kurt, are those bilevel cars smooth-sided or are there some ribs or corrugations? If you plan to add anything to the sides with liquid cement, remember to brace the sides somehow from the inside. It will help prevent warping over time. Also, if you're doing laser cutting for the sides, did you consider having the windows laser cut to fit? It's extra work to install each window, but how cool would it look! :-)

Mike Bartel
IHP
http://ihphobby.tripod.com" onclick="window.open(this.href);return false;
http://www.shapeways.com/shops/ihphobby" onclick="window.open(this.href);return false;
 #1205963  by Kurt-Trirail
 
Mike@IHP wrote:Kurt, are those bilevel cars smooth-sided or are there some ribs or corrugations? If you plan to add anything to the sides with liquid cement, remember to brace the sides somehow from the inside. It will help prevent warping over time. Also, if you're doing laser cutting for the sides, did you consider having the windows laser cut to fit? It's extra work to install each window, but how cool would it look! :-)
They are more or less flat, but there are three ribs on the prototype which I've imitated with 1x3 Evergreen styrene (see below). I'll wait to reinforce it until I glue the sides to the roof kits and have the ends printed. Always easier to reinforce when the car is already square (and you know how much clearance you can get away with, given the interior).

Image

I do intend to have the windows cut to match, if not prohibitively expensive. Perhaps I can get it done in smoked acrylic to better represent the prototype. I intend to spray-tint the Athearn cars I own as well; the clear windows don't do the cars proper justice.

-Kurt