Building an E&N curved steel viaduct

[Cajonpassfan]

Is that a lot? It’s what I measured. 

Managed to get all of the foundations cast this week!



Craig

Yea, 7" is a lot, if that's the actual elevation difference between the outer and inner rail (which is what superelevation is). But if it's the elevation difference at the end of the bridge ties then (I can't tell from pics) it's probably okay. Besides, a little exaggeration looks good😎
Otto

[craigolio1]

Yea, 7" is a lot, if that's the actual elevation difference between the outer and inner rail (which is what superelevation is). But if it's the elevation difference at the end of the bridge ties then (I can't tell from pics) it's probably okay. Besides, a little exaggeration looks good😎
Otto

Awesome! Thanks for the info. So I measured the thickness of the wood under the ties on one side, that wasn’t under the other side. So I figured that was it but I may have missed something.  I should have taken pics.

[craigolio1]

Today the bridge deck got guard rails. They are C40 and after sanding the bottoms I soldered them on to the PCB ties. I cut them to length but didn’t shape the ends yet. That will happen when I install it on the module.



After the soldering was done I gave the deck a bath in warm soapy water and scrubbed with a soft toothbrush to remove any flux and other contaminants. Now it’ll dry for a few days and the track will be ready for masking and a base coat of black on the track.


Also this week I worked a little on the foundations. I removed the over sized bits of plaster that are to represent the form lines, by dragging across them with a knife.

Then I experimented on one applying a diluted wash of India ink. I was expecting it to darken the plaster and also dribble down and collect in the details. But instead the plaster is so porous that it immediately soaked up everything I put on it. More like a wood stain. So basically i ended up dying it dark grey. That’s darker than I want it to be but I can live with it. But I think I need to figure out another process. I don’t have much experience with plaster so any advice is welcome.



Right now I’m thinking do the others the same as this, but then maybe apply a flat clear coat of enamel to stop it absorbing so much. Then another black wash to hi light? Then dry brushing?

Craig

[Dwight in Toronto]

Wow Craig, that concrete finish looks pretty convincing to me just as you’ve done it.
Great build!

[craigolio1]

Wow Craig, that concrete finish looks pretty convincing to me just as you’ve done it.
Great build!

Thank you.

[craigolio1]

I decided to try using anchor cement as was talked about here recently.



The results were iffy for the first couple of try’s until I got the mixture right.





But I managed to make several successful casts and I’m quite pleased with the results. I’m going to use these instead of the plaster casts.

After they had cured I knocked down my “form lines” using 80 grit emery paper.




On all but one it gave the intended finish. You can see one looks eroded and pitted. This is an earlier cast that was a drier mix. I decided to keep it but I rubbed some wet cement on the outside to smooth it and make it look less like an ancient monument.



And I now I have all of the foundations I need. 





I also made some good progress on the bridge. I weathered it using two Testors washes I found at Michael’s.



I painted the inside guard rails using Valejo Grey/Black. I haven’t done the running rails yet. I’ll do them then I paint the rest of the module

I also built the refuge platforms.











Finally the towers were epoxied to the girders and the bridge is done!



The bridge fits in place on the module.



However I built the module before I took my trip out west and hiked up to the bridge. Now that I’ve seen the bottoms of the canyon I see there needs to be some re forming of the landscape. Particularly to fit the foundations.





But then the whole canyon will have to re shaped to match.

So that’s where I am now. Very good progress, and now it’s time to get messy and redo the canyon!

Craig

[Olivani]

Stunning Craig, absolutely stunning. I like the rust weathering on that bridge and the concrete pieces turned out very realistic, good job.

Oliver

[craigolio1]

I found some time the last couple of days to get back to the module.

I removed the needed material to fit the bridge, abutments and foundations.



I also made the molds for the abutments, and poured them in anchor cement as well.









The top of the abutments has a curb cast into it to represent the sides the prototype, to hold balast in. On the prototype there is a depression which allows a tie to be placed right at the end so I added the same to mine.



The finish in thr ambutmets was nice and smooth but the splotches bothered me. I think they were likely due to the alcohol I sprayed in the mold as a wetting agent. Since the molds were a one time use thing I decided to see if I could change the finish instead of making new molds and pouring again.

First I sanded the sides. The darker patch is a swipe of cement I put on to fill some bubbles.



Then I mixed up a very lose mixture and poured it on the wides. I let it settle a bit first so none of the sand came out. Just the cement.



I spread it all over and let it dry resulting in this.



It’s all improvemnt but still didn’t eliminate it. I’m going to roll with I though. Concrete is never perfect and this will require a ton of weathering. The prototype is covered in lichen and moss so I think in the end I’ll be satisfied.

The next step was to fit the abutments in to the module. I started with the big end. I carved it a niche and removed the cork road bed since the ties will sit in the concrete surface, to be ballasted later.



I layed down a bed of PL Premium and pressed the abutment in. I used shims to suport it and then held the bridge inplace to check alignment.





Placement was bit tricky as the bridge is on a curve.



Looks like I’ll need more moss and dirt than ballast.





I’ll let that cure before I move onto the other end so I don’t move it by accident.

Edit:

Hmmmm. Looking at the last pic, the concrete doesn’t extend into the landscape on the left. It’s really only an abutment on the end and a retaining wall in the right. Once this all sets up I’ll have to get out the grinder and see if I can remove/taper the left side. Wish me luck!

Craig

[craigolio1]

Stunning Craig, absolutely stunning. I like the rust weathering on that bridge and the concrete pieces turned out very realistic, good job.

Oliver

Thank you!

[craigolio1]

The other end was small enough I could align it by eye/feel so it went in too.



Next step is to get the bridge fixed in place and shim up a couple of the feet on the main tower to get it all level. Then I can install the concreted foundations.

Craig

[John]

I love the in progress shots .. as the politicians like to say - making the sausage is messy

[amato1969]

Hell yea, epic build!

  Frank

[craigolio1]

Thank you everyone.

[craigolio1]

With the abutments dry and firmly in place, I can now move on to setting the bridge supports.







The first thing to do was to get the module level (I should note that I did not do this first but it’s probably best practice so it’s first here). My modules site on heavy duty adjustable shelves and last time I set this one in place I didn’t do any levelling so some shims took care of that. A quick check on a non super elevated portion of track confirms.



It should be noted that the track on the bridge is NOT level or plumb at this time.



 The bridge is curved and so the tower is pulling it out of plumb, and also the weight of it is causing a slight sag while it’s unsupported. Not super relevant at this moment but important to keep in mind as I progress for sure.

It easy to fix though. I discovered that using the weight of the level if I slide it off one side it puts a bit of torque on it and levels right up. This will come in handy.

 

On to construction. I need a good base to support this thing. So I found some thinner foam and cut a piece to fit in the canyon floor. I glued it in with PL Premium.



Then using shims and toothpicks, set it’s final position. I positioned it so the foundations are just shy of the bottoms of the tower legs.



 The goal today was not to support the bridge. It’s to build the base. When it comes time to install the bridge I’ll shim them to the correct positions so that the bridge is plumb and level.

Thats all for now.

Craig.

[craigolio1]

Today i used the old wooden stand in part of the bridge as a form with which to remove a slight dip that somehow found its way into the bridge. Through all the steps that I tried really hard to make it perfectly flat but somehow I missed the mark, so I’ll have to fix it in post.

But first I had to mark the locations the footings will be when plumb so I used my level to plumb it and then placed the footings in their correct places, marking the locations with a pen.



I then taped the wooden part to the bridge to pull it up to level.



Now I know exactly where the footings need to go and I can shim them up to meet the bottoms of the towers. 





Unfortunately this process will have caused the ends of the bridge to lift a tiny bit but I’m confident that when I glue it in place with weights it will be held down. It takes very little effort to hold it in place.

As far as the installation goes the next step would be to glue these foundations in place but I think I’ll weather them and put all the moss and lichen and such in them since this will be awkward to do on the insides if done in place. Some of that will be covered by scenery but I think it’s worth it to save the aggravation.

Craig