The Micro Engineering Code 55 bridge track looks great and it comes with Code 40 guard rails. I used it on a previous layout. Have one bridge on module 10 that I'm going to use on my current layout. Joe
Nice progress, Stephane. Haven't checked on this thread in a while. Things have progressed well. The bridges look really great.
Thanks RailMix! Still working on the bridge, the angles are making it tough (curved deck on a slope!). I'm just going to use Atlas flex track, and the deck will be ballasted... Here's the work on it so far! The proportions are not final. The deck itself would be concrete, much like the one seen here...
Time to finally fire up the printer. I probably should have made some test prints, but with my head in Fusion 360, I got carried away and just kept going. But now it's done, and will start trying to print this thing... I should be able to print each of the four bridge sections, followed by the piers and the abutments. One of the piers is longer than the rest because, fingers crossed, it will end up half in the river, half on shore. I still need to bring the piers into Blender to add a stone texture and hollow out some of the solid parts, but I will be sending the first bridge section into the printer today! yay!
About five hours into a 14 hour print!! Sucks that the middle bar of the railing didn't print correctly, that's very weird. It's 0.5 mm thick, which I've successfully printed before, but maybe not at this length. Oh well, let's see how the rest prints before making adjustments. Honestly though, it might be easier to just buy some styrene and use thin piano or brass wire to make the guard rails. They'll be stronger. I can easily cut off the existing railing. I am a bit nervous though. The bridge sections are exactly 150.39 mm long, I added 4 mm of supports. Technically, the Anyciubic photon has a max print height of 155 mm, so I'm really pushing it here!! I really really hope the entire bridge section prints!!!
Those viaducts will be beautiful! I just use Kato Unitrack single track viaduct sections, with ballasted track included. WAY easier, but not nearly as beautiful. Kato has also come out with some curved bridges too.
You might be able to find etched metal railings too. Gold Medal Models makes some; they were the first product I found online. That might be easier than trying to assemble railings from stanchions and wire.
Oh, wow, I got all excited there for about five minutes! I even found some of the industrial railing in a Canadian hobby shop for a little less than it would take to order directly from Gold Metal Models once the exchange rate was figured in. For 25$ CAD, this gives me 300 scale feet. A single bridge section needs 291 mm of railing, times four sections, brings me to 611 scale feet required! Probably a little more since I need to waste a little to make the ends match. That's three packs of this expensive stuff (do they make this stuff in actual gold?! yeah, I know they don't, but man that's expensive detailing!) Anyhow, I need to find something else, I'm not paying 75$ plus shipping in railings. I do need to remove the railings. For now though, the bridge did print in it's entirety! That's the good news. The bad is that even the top rail warped. I'm still scratching my head on that, since I have successfully printing parts this thin, but each rail section might be just a little long. I'll get a picture up soon, still washing and curing the two sections under UV light. BigJake, I saw those Kato bridges, and they do look nice, and certainly would be easier. But I needed a very specific radius and length. I do really like the Kato bridges though, and I have two of them on the layout! Plus, Each Kato bridge section is 20$. I spent some fun time designing the bridge and then about 3$ in resin for two sections
Here you go, this is what the sections look like. I'm going to beef up the railings a bit and print two more sections. I'd rather have slightly thick railings than pay through the nose for nicer railings
Heck yeah! Those railings pass my eye test! $3 in resin, and how much in the printer? I know, the printer can be amortized across multiple projects, but that first project is really expensive! On the other hand, so are locomotives...
I agree, move on and I'll bet you never notice them down the road. I've built 3 of my houses and always had mistakes in the building process. Could I point them out to you now? Nope. New mistakes help to forget past ones . Nice design work on the bridges. About the cost of a printer. If mine had a major breakdown now I'd have another one ordered tomorrow . It has been one of the best things I've spent money on in the last few years. Love the design side of it, Sumner
30 or so hours of printing later... All bridge sections are printed, and the two abutments. And yes, I did reprint the first two sections. I wasn't happy with the railings. They were too high, and too warped. The top section is the new print, and you can see the old section down below. The new railing are 3 scale feet high, the first were 4 feet or so. The rest of the viaduct section stayed the same. Funny thing is that I detailed the area between the girders with cross beams, and I'm not sure it'll be visible from any angle on the layout! So right now, I'm currently printing the three piers. This is an 11 hour print, and will be finished tonight around 9 pm or so. But here's a preview the stone texture I added to the piers... I'm a bit worried about the footprint of the first (longest pier) getting too close to the track that crosses next to the river below the viaduct. It's going to be tight! On another note, yep, I'm with Sumner - despite the cost of the machine, if the photon broke down I'd be replacing it in a heartbeat. I haven't even printed all that much with it, but I love designing parts and seeing them come up on the printer. Now that I'm getting closer and closer to working on scenery, I suspect I'll be using it more and more. As for the price, honestly, it costs less than a DCC sound locomotive these days!
Man, that's awesome! I wish I had the skills to do that! You've definitley tightened up the rails on the reprint. Very nice work! You should post this stuff on the 3D Printing thread...
But you will know they are there . When I saw them I wondered will the crossbeams print without supports?? Very nice work!! Sumner
Stephane, Please forgive my ignorance, but why print straight bridge sections with angled ends to create the radius you require? Do 3D printers not work so well printing a radius that large? Is it a material usage efficiency matter? Or is that a more prototypical approach to how a bridge like this would be constructed?
On my first print, the diagonal cross beams did in fact warp a little. I now realize that I did a final rise of the part in hot tap water and that's what caused much of the warping, including to some extent the railings. The cross beams are all 1.25 mm thick, and built in an L shape. I was worried they would need support, but they all worked fine (I was never worried for the diagonal beams, which wouldn't need support, only the horizontal ones). I based myself on one photo. Specifically the viaduct found at this link here. The trees hides the rest of the viaduct, so I don't know if the entire thing is curved, but the last two sections do form a curve. Notice that the concrete deck and the girders underneath are formed of straight sections. Obviously I'm using a much tighter radius, so the end has a stronger angle than the real thing. But if you google images of curved deck girder bridges, you'll notice most of them are made of straight sections. Though when the deck is made of wood instead of concrete, the deck is then properly curved. So I used that photo as inspiration, but made changes such as adding railings to both sides of the deck, and I used stone piers similar to another viaduct photo found in Ontario. I'm sure an engineer type person could find plenty wrong and unrealistic about my viaduct, but that's okay
Thanks, with my FDM printer it can generally handle angles 45 degrees and greater from horizontal without support, but less than that is real iffy unless it is a short distance. I've gotten away with horizontal window openings of about .150 without support but that is about it. Yep, I'd think to economically make them they would have to be straight. The side vertical panels are basically trusses with the vertical part doing the load carrying and the horizontal components and diagonals stiffening and holding vertical panels in position. Making all of that curved would be a lot harder to make and more expensive and a one off for every bridge basically, Sumner
There are a few reasons for straight-segmented curved bridges. One is that, early analysis techniques for the strength of curved structures were more complex and difficult (read: expensive), and straight structures were already well understood and easily applied. Second, fabrication of curved structures (at 1:1 scale), unless cast, is also more difficult (read: expensive), more than offsetting any gains from less material. If you've ever been to a railroad museum with a variety of older and newer locomotives and rolling stock, you can see that over time, the same parts were made lighter and cheaper, due to advancing analysis techniques to predict strength of more complex shapes. You can see it in the sizes of the cross-sections in railroad trucks. And in differences between older and newer steam engines (connecting rods, wheels, chassis, etc. Some of this was likely due to improved steel/iron manufacturing techniques that had less variability in the resulting strength of the parts. With less variability, mechanical engineers could design closer "to the edge", with lighter, more efficient structures that were cheaper and lighter weight (they too had to move right along with the freight on the railroad, but that weight did not generate revenue). My favorite example of advancing technology, even in the steam age, was a simple innovation that greatly improved safety of steam locomotives. The stay bolts that suspend the firebox in the rear of the boiler extend from inside the firebox, through the water jacket in the boiler, and out through the boiler sides. They are under tremendous stress from heat and cold, expanding and contracting of the boiler and firebox, not to mention corrosion. So they crack over time. When enough crack, they break, and the pressure in the boiler overcomes the remaining stay bolts, and explosively shoves the entire firebox back through the cab, killing the fireman and engineer (and anyone else in the cab) by blunt force trauma, steam burns, fire burns, etc. The problem was knowing when enough of the bolts began to crack and weaken, before ultimately failing. Some enterprising engineer (not the kind that drives the locomotive) figured out that he could make the stay bolts partially hollow, closed on the firebox end, but open to the outside of the boiler. Since the hollow section was the weakest point, any crack would develop there before anywhere else. And once they cracked, they leaked a little steam from the boiler, out through the hollow vent, outside the boiler, where it (or the condensed water) was plainly visible, making periodic inspections easy and effective.
