Laser Etching a Stone Arch Bridge's Facade

[railandsail]

Lower Portion of that Viaduct

As the viaduct approaches deck level, the arch structure is no longer utilized,...just stone sides, no arches

(there is that alum grade tool again)

Turns out there is not much need for visible arches here anyway, as they would likely get lost behind some of the buildings I might place along here,..for instances

[railandsail]

Finalize Subframe Structure of Double Track Portion of Viaduct
(and perform open heart surgery...ha...ha)

I went back over to the double track portion of my viaduct to finalize and tweak its vertical support piers.

 
I have this long piece of stiff aluminum 'door sill' that I have been using to get the grades smooth,...ie..




I was under the impression that I had the upper portion of the viaduct done already. But then I discovered I needed to provide slightly more clearance under the bridge portion so as to clear double-stacks coming into port from that access track underneath. Plus, I discovered that I need to re-level the basic plywood deck down that side of the layout (long explanation deleted). So all my previous measurements, and the already cut support piers were going to have to be replaced or re-cut to new dimensions.

As if that wasn't enough of a disruption I discovered another problem affecting the viaduct on that side. It turns out I have two sheets of plywood deck meeting in that area,..and forming a corner piece.
(hidden under that paper template)

 

I was going to have to perform surgery ( I kiddingly referred to it as performing open heart surgery),...cut back the covering paper template, roll it up, so I could access the innards.

I put a 'backing plate' of ¾” plywood under neath such that it got glued and screwed to both deck pieces of deck material, plus it got an extra corner piece glued and screwed in as well.




That is wax paper hanging there to keep from gluing all this mess to the metal bench work

 

Now I can get on with the FINAL cutting and fitting of the viaduct frame.

 

 

 

 

 

[railandsail]

richhotrain

That raises an interesting question. Is your railroad climbing to cross a waterway or grade level tracks, or is it crossing a ravine or some such depression from grade? Perhaps you can keep the stone arch system level at full height over the depression. I hope this makes sense. Rich

My single track viaduct there is rising from ground level to fly over another track that is entering the central peninsula (with double stack containers traffic). It is also connecting up with the double track portion of the viaduct that is entering the back wall tunnel to proceed up the helix on the other side of that back wall. Bottom line is that track has to gain a minumum of 3.5 inches elevation.

BTW, its a fairly steep grade, and I hope that most trains using it (at least longer ones) will be using the downgrade rather than upgrade.

[richhotrain]

railandsail

I am still inclined to continue the arch shapes a bit further down the line. I think I was influenced by this photo, even though it is hard to discern the exact construction as things get lower

There is something interesting going on in this photo. The track may or may not be descending, but the roadway next to it is clearly rising. That raises an interesting question. Is your railroad climbing to cross a waterway or grade level tracks, or is it crossing a ravine or some such depression from grade? Perhaps you can keep the stone arch system level at full height over the depression. I hope this makes sense.

Rich

[Overmod]

railandsail

I am still inclined to continue the arch shapes a bit further down the line. I think I was influenced by this photo, even though it is hard to discern the exact construction as things get lower https://thecourier.typepad.com/alongtherightofway/2014/08/bellaire-viaduct-then-now.html

You can certainly do that; just be aware of what the footings on each of those smaller arches have to be doing even if (for whatever reason) they are below ground level.  Part of the issue is that you're by necessity using selective compression on the approach angle, so you need to use a little care in how the 'arch' stones are arranged under the courses of stone that are effectively forming the 'ballasted deck' of the overall viaduct.  You might have to do some careful cutting out and rotating of the arch stone sections within the 'portal opening' to get the keystones actually at the top of the opening and the springings symmetrical for the lower arches...

In areas of uncertain soil, for example, or if you wanted a more 'permanent way' construction for anything elevated (perhaps as in the example) you could easily prepare the 'foundations' as piers right down close to the ground (as I think I see being done when I blow up the picture and do a little contrast tinkering on it).

The stone above the arch heads to the level of the 'deck' remains constant for all the arches, as it should for this kind of construction*.  I would suspect that all the approach arches are similar in dimension as well, although I'd be very, very happy to see a picture taken at 'right angles' to the provided one that shows the arch detail on the OD of that approach curve.

Under these circumstances carry right on taking the arches close to ground level.

 

*Something to be careful of is to maintain the PROTOTYPE thickness of 'deck' stone courses over the heads of the arches for your particular scale.  As I look at some of the work in progress it looks as if your 'scaling' of the printed arches may not be close to 87:1 and the deck therefore skimpier than it should be for the 'low-down' portions to be quite right...

On the other hand, if you look at 'Starrucca' you may be struck by the relative lack of stone between arches and track.  If I hadn't known that Erie operated considerable Berkshires over this at speed I'd have said it wasn't safe, but it is.

[railandsail]

@OverMod,

Very eloquently written reply. I might just try some of your detailing suggestions.

But I am still inclined to continue the arch shapes a bit further down the line. I think I was influenced by this photo, even though it is hard to discern the exact construction as things get lower

https://thecourier.typepad.com/alongtherightofway/2014/08/bellaire-viaduct-then-now.html

[Overmod]

railandsail

I assume this 'technic' of yours could be used to make the different/same arches appear 'different' ??

It can, but a better one in your case will be to get one of those sets of art markers in a wide variety of colors, or watercolors, and dab on a few random spots of color blended in with appropriate thinner afterward.  A little will go a long way.  You can use opaque grays or tans if something doesn't come out the way you expected.  Note that you could also cut and tile the laser-printed image 'stone' and fill in any gaps with a little handwork if patterns are still a bit too obvious...

Then surface and tool with translucent or 'clear' material over the top.

Someone gave you dubious advice about 'all those arches being the same'.  An arch of this kind will have its 'springings' adjacent to the vertical "column" and will have its proper form for best strength between those two points.  It will not, as yours currently does, look as if the arches are sagging down into the earth like some ancient-Roman-ruin folly.  As noted, in all probability this approach would be built as a fill -- longer-lasting and much cheaper -- up to the point an arch is necessary, say for a street or passunder, at which point it will have retaining wall(s) and arch construction to suit.  Then the fill, perhaps with stone lower retaining walls as with PRR's elevated construction through places like Mount Union, would continue until the elevated arch structure can be commenced with proper shape.

In the age when stone arches for structure was the 'done thing', making fills without power equipment was a long and tedious process (see for example all the Chinese with baskets on the Central Pacific) whereas construction in stone was more expensive in materials or craftsmanship but more permanent, easier to 'foot', and easier to keep free of effects from water drainage of various kinds.  Later, railroads would consciously use the idea of 'timeless stone construction' (as with many of Cassatt's projects) for an added sense of monumentality, perhaps as stone 'veneer' over concrete.  My suspicion is that your approach uses the latter.

Now, I'd argue that this would be done with 'sections' that have a consistent arch size, starting with smaller 'bays' and going to the full size as you gain height, or get to the point a greater span/fewer footings are required.  To avoid the Chinese-wall effect you might go to small arches as soon as you get to 'human head height' underneath, with appropriately-scaled column thickness, and transition to larger arches as soon as you have room to carry the arch down to proper transition to springing.

Part of the fun here is that longer elliptical arches were certainly used, but they would seldom be built in this type of rounder-headed stone construction.  There is a recent thread discussing both the appearance and construction of this type of bridge or viaduct on the Trains Magazine forum (helpfully in the 'non you-know-what forum' thread) and some other useful thoughts in the 'Filling in a trestle" thread.  

Still shallower arches are possible in viaducts, but there you would have to remember that vertical and horizontal load on such an arch are handled differently, and explicitly, via the form of support at the springing (which can be very high up on a support column or pier, but has to be balanced in thrust on the 'other side').

[railandsail]

Single Track Portion

Couple of days ago I finished the substructure of that portion of the viaduct that supports the single track that sits behind the turntable area and in front of Balt. The roadbed and the vertical supports are all constructed of that cellular PVC material I've spoken of,...and glued together with PVC cement.

In this photo I picked the whole structure up and moved it out to my carport work bench for some final tweaking, and tapering down that end that reaches ground level.

 

Here is a little close up of some scraps of that PVC material I used.

BTW, having a chop saw was really handy in getting those very straight cuts,...and a piece of 180 sandpaper lying flat on the table top made cleaning any flash a breeze.

 

Now I can get on with a the final accurate location of my turntable and its roundhouse,...and subsequently the trackage associated with it. I was going to go ahead with cutting the big hole in the 3/4"plywood deck for the turntable, but my friend suggested wisely that I wait to do that outside the shed, as the router cutting that big hole would make quite a mess.

 

 

[railandsail]

Also, the width at the base of each where each arch meets should be the same width, even though the arch is getting shallower.

 

 Glad you brought this subject up, ....so I had a new look at the situation today. Turns out I CAN made those base dimensions more uniform,..simply by the way I cut and paste the master image. I did this quick little experiment today when I cut the original 6" wide image down to 5" wide for those shorter arches in the lower portion of the viaduct. This cut-and-paste cardstock method allows for such possibilities,...that would have been much more involved if I were using plaster moldings.

 

Lets see if my crude photos show the difference.

original wider bases




....narrower bases on those last 4

 

BTW, that's the famous clock tower in downtown Baltimore (background to be there in that corner). Going to have to make a cardstock image of that as well.

[railandsail]

Interesting idea,...I'm new to these scenery technics, but I think I get what you are saying?

I had another gentleman suggest,

While that color picture may be great, making a dozen copies or more of the same one won't look so great. That photo has very distinct color markings on it, and if every arch had the exact same markings, it wouldn't look very good.

I assume this 'technic' of yours could be used to make the different/same arches appear 'different' ??

[Overmod]

jjdamnit

Check out this web site for patterns... Textures.com.

Hmmmmm... I wonder...

... if he sprayed the printed image with appropriate impervious varnish, and then applied something like Mod Podge that would dry clear, he could stipple up the surface (with techniques like those for making realistic water, perhaps) to give some 3D surface effect in light and shadow.  That is about 100% the effect that can be seen in the full-scale picture of the 'flat' arch and voussoir faces of the Thomas Viaduct linked above...

[BigDaddy]

I've seen that bridge somewhere.  Actually I was stupid enough to walk across to see the monument on the other side.  1/2 way across, I realized I couldn't out run a train if one came along. 

[MisterBeasley]

How many arches are you planning to need?

If you could either buy or craft one full 3D model, you could create a mold from liquid latex and cast more.  I did this because I needed thin tunnel portals.  I found it very easy to paint the castings with rattle can spray paint.  I find that Rustoleum's textured, speckled paint gives a very good appearance, and the painted Hydrocal castings can still be hand-painted with a wash of India Ink to deepen grooves, which lets you individualize each arch.

This can go quicker if you do one or two castings a day, and collect a bunch so you can paint a whole bunch at a time.

[jjdamnit]

Hello All,

Check out this web site for patterns...

Textures.com.

Hope this helps.

[Doughless]

railandsail

I just received this photo in an email from a gentleman who maintains a large blog about the Thomas viaduct. I believe this may have to become my 'master' from which to make photocopies for my cardstock model.

I think the use of this image solves my 'color questions'.

Perhaps I should even trim the image so as to leave the inner portions of 'arch ceilings' in place even though they would not really been seen by a viewer from 'above'. ?? (they are just so representative of the real thing)

 

Not sure exactly where you're going with this, but I would be careful to use a photo that has a 3D embedded angle of viewing into the image.  If you use the pic in its entirety, including the inner arch ceiling and walls, it will only look right on your model if you happen to be viewing the model at EXACTLY the same angle the photo was taken.  Which is straight on and below the peak.  On your layout, you will be looking at it from the top and sides most of the time (and the angle will change as you walk around the layout), so you should never see the ceiling of the arch, JMO. 

Therefore, any fixed 3D angle you paste onto the cardstock is going to detract from the model becauee you will never be looking at it from the same angle, yet the 3D imaged will always be fixed upon one viewing angle. JMO.

I would build a blank 3D model in cardstock or foam board, including arch ceilings and walls, then simply line them with a flat photo of the stones.  

For your front profile, I would keep it simple by trimming out the 3D innards and using the face on your face of the cardstock.

Short version:  Don't cheat by trying to get a 3D effect from a photo.  Build the viaduct in 3D and line it with photos accordingly.

Again, JMO.

 

[Overmod]

Late to this party.

One of the 'keys' to making this work is to use 'trompe l'oeil' techniques to give more "3D" illusion to casual viewing.  For that you will want to process the image a bit to get more contrast where the 'shadows' would be -- in general, the illusion that the surface is rough will be the 'best' thing, probably more than color fidelity.  Some one of many here who knows the ins and outs of image-processing software can guide you effectively.

In the black-and-white laser days I ginned up some things which I subsequently hand-tinted with watercolors.  (You can easily build up surface detail with appropriate acrylics or oils, but that wasn't in my 'skill set' then...)  Hand overpainting might still be an option in these inkjet-and-color-laser days if you want heavy black in the image.

If you glue the resulting laser-printed image on cardstock or foam you can tool the surface with a stylus for more 3D detail short of trying to carve everything on foam.  When I was young and more enthusiastic I briefly tried vacuum-forming a thin layer of printed film over a carved substrate ... didn't follow up, and of course 'hobby' vacuforming in general is now viewed with some safety horror ... wish that would change!

Don't try the forced-perspective 'leaving the inside arch detail' -- it only works from a viewing angle similar to the original, and is very obvious off-axis, in particular for typical model-railroad high angles.  What you could try is making a jig of some kind to use 'panorama' on a cell-phone camera to make a strip picture of the whole inside, then print that and use it on flexible material to form the arch.  Or just tile and do a little overpainting to hide the joints and repetition...

Yes, wrapping projecting detail with the paper stonework ought to work.  You will probably need a little touch-up 'filling' and painting, but that could probably be done with only 'weathering' or 'shadow' colors...

By the way, I haven't seen this in the discussion but it might be there: When you're done with part of the fabrication, spray well with a good damar/Kamar varnish.  You can overwork this with more detail, but it won't fray and pick up dirt and other crap to look dingy and fake with time.

Also incidentally: I like your use of 'scale detail' railing material; note that on the pictures, the 'lacy' railings draw the eye more than the strict stone detail.  This might be a place to invest in some etched railings, or even the technology to make them, as a little of the stuff on the 'right side' of the arch photo would dramatically show 'realism' even if your stone were substantially flat...

Incidentally, the whole issue of stone viaducts used for approaches might be technically interesting.  There would be a couple of time ranges (comparatively constrained) where a railroad would use this -- one period being the general age of Starrucca/Thomas where railroads 'built for the ages', ending somewhere between Bessemer steel and the era of the Phoenix Bridge Company, but having a resurgence on roads like PRR that didn't like the Lackawanna white concrete modernity style.  The thing is then that inclined stone-viaduct construction might not have the proportions and structure you are copying from other stone bridge types -- not that this is critically important, just that the design problems and material use for 'best' structure may be a bit different.

[railandsail]

I just received this photo in an email from a gentleman who maintains a large blog about the Thomas viaduct. I believe this may have to become my 'master' from which to make photocopies for my cardstock model.

I think the use of this image solves my 'color questions'.

Perhaps I should even trim the image so as to leave the inner portions of 'arch ceilings' in place even though they would not really been seen by a viewer from 'above'. ?? (they are just so representative of the real thing)

[railandsail]

I'm wondering if I can just use my own image to print out multiple copies I could mount to cardstock or slightly heavier styrene or PVC board.

I figure I could use this image (or a better one if available) modified to my required dimensions (6" inches from center of proud column-to-center of proud column).

Then perhaps make seperate images of those proud columns and wrap them around a circular piece of cardstock and paste them onto the flat faces such that they covered up the joints between adjacent arch sections.

Just have to find the best image to use as a master (if this one I have shown is not the best?)

[railandsail]

trevorsmith3489

You might consider this company

https://scalescenes.com/product/r017-viaduct-arches/

Trevor

 

I had some trouble naviagating their website, and I could not pull up a larger image of the stone face vs brick faces they offer?

[trevorsmith3489]

You might consider this company

https://scalescenes.com/product/r017-viaduct-arches/

Trevor

[railandsail]

Just found this video/process,...I LIKE IT

Printable bridges & viaducts
https://youtu.be/5W4_n8HfSjc

no messy casting of plaster or plastics,...then no painting and weathering,...etc

I'm SOLD on this idea

[railandsail]

Downloadable Cardstock / Paper Patterns (help interpret)

Lets see if I have interpreted this website's info correctly?

https://www.modelbuildings.org/bridges-and-tunnels-pack-deal-c/
(there is a video presentation there also)

I believe it is saying that you pay a one time fee to download an image,...then you can make multiple copies of that image?

Is it saying you might print that image onto a variety of materials,...like for instance relatively thick cardstock?....or other material that you might get to operate in your printer?....or some material you might get to operate in a more modern type printer??

[richhotrain]

Here is a pretty cool project:

http://www.gatewaynmra.org/2010/casting-and-scratch-building-stone-arch-viaduct/

Rich

[mbinsewi]

Not the same bridge as above, but I found this on a web site named Dreamstime , and I found these photos of the same bridge  which is in Janesville WI. used by the UP.

Like I mentioned earlier, I would carve them out of styrofoam.  It looks like only the side facing out would need to be detailed.

Mike.

[railandsail]

I have decided that I do not need that much detail on mine, and will likely go with just  good quality 'printed on paper stone work' with some sort of proud columns.

Wonder where I might find the best quality photo of that stone/arch facade to 'adjust/photoshop' to an image that can be repeatable reproduced like I did with my xerox copies for the mock-up?

[railandsail]

Doughless

I think it looks pretty good as is, with maybe more honing of the color to look less gray.  Kinda looks like a simple black and white photo rather than a color image.  And I would think about adding some sort of liner on the inside.  Lots of dark shadows there, so you wouldn't see much detail at all beyond a few feet of the inside.

Many modelers are beginning to build structures in the same way.  Highly technical and crisp digital photos glued onto simple foam board.

You are correct there, I just mocked it out quickly with black and white printer. Perhaps a color printer would do a better job

 

 

While the columns or pilasters in between the arches look good, you may want to try to add a bit of 3D texture to them.  Place a strip of styrene under the photos slightly narrower than the columns.  Then when you crease the photo around the column as you glue the whole thing, the column stands a bit proud of the remaining arch.  A little actual 3D texture if you want to go that extra step.

I think that if you cut the photo and then add somehting to it, it will show rather badly.  I'd want to photo to stay seemless by simply putting something under each column then wrapping the photo over it.

I like that idea for making those columns 'proud'. And I would like to extend their height to form part of the 'hand-railing post'

 

 

[railandsail]

Don Z

Not trying to be the wet blanket to this party, but do you think a railroad would really go to the expense of buidng all of those arches instead of using fill for the upslope until it reached the spot where the span is needed?

I know, I know...it's my railroad and I'll do it my way. Too many arches was the first thing that caught my eye.

Regards,

 

You have a point there Don, I just may have to take that into consideration.

[mbinsewi]

I think it depends on what's on each side of the viaduct.  I think what Brian is doing is more like the approach to the St. Charles Air Line bridge, in Chicago.

Air line bridge by WC4ever, on Flickr

From the very start of this viaduct, it's on a structure, and not fill.  This screen shot courtesy of RailStream's Chicago cam.

Mike.

[Don Z]

I was talking about the APPROACH to the bridge.

 

Don Z

Not trying to be the wet blanket to this party, but do you think a railroad would really go to the expense of buidng all of those arches instead of using fill for the upslope until it reached the spot where the span is needed?

I know, I know...it's my railroad and I'll do it my way. Too many arches was the first thing that caught my eye.

 

 

 

How about the Old Stone Arch Railroad Bridge in Minneapolis? 

 

There is a prototype for everything.

Rich

 

[/quote]