Building a curved viaduct....

[The Black Hat]

Hello all... 

I'm doing some research for a project I am getting involved in and it will involve a curved viaduct. 

As a result, research is bringing up some interesting results. Do any members have photographs of viaducts built using the following products:

1. Wills Kits OO SS80 Three Arch Viaduct

2. Faller 120466 curved viaduct. 
3. Langley models stone viaduct kit. 

Any photographs or dimensions would be great. I am wondering if the Wills kit can be made into a curved viaduct, or how tight the radius is for double track using the Faller model. 

Thanks in advance. 
 

[Phil Bullock]

Might be worth having a chat with The owner of Blueball Summit … @andy stroud

[sjp23480]

Also check out @Physicsman thread - Gill Head - which has a very nice representation of Arten Gill viaduct (Settle Carlisle) with detailed instructions on how it was built.

 

WRT your original question, I have looked closely at the Wills kit, but they would have to be cut into individual arches to negotiate a curve, it will need a replacement deck and the piers will need to be infilled on the outside to take account of the curvature of the structure.   

 

Jeff @Physicsman produced the following diagram which most effectively illustrates the effect I am struggling to explain.

 

Not sure if this helps?

Steve

 

 

Edited November 24, 2022 by sjp23480

[JZ]

I built a four arch Will's viaduct on a gentle curve. I inserted a 4mm square Plastruct rod in joint between sections. The curve was gentle enough that it didn't look like straight sections. Any pictures I have are 12000 miles away at home on my PC and the old layout thread lost them in the historic RMweb meltdown.

[The Johnster]

Depends on how sharp the curve is.  Gentle curvature will enable you to get away with short straight viaduct sections an arch at a time without it looking too much like a thrupenny bit, but when you get down to sub-3', and especially down to setrack radii, you'll be in trouble with the Wills or Hornby items; not familiar with the Langley, but I reckon you're looking at a scratch-build.  I'd make it out of sheet plastic, about 20-25mm and face it with brick or stone paper or plastic sheet.  Start with the inner radius wall and cut the arches into it, then mark the inner radius on the baseboard and bend the plastic to fit to it, then mark the outer radius to the same centre point furher out concentrically to the required width of the viaduct.  Mark the positions of the base of the piers, parallel lines for each arch, so that the piers are slightly tapered outward towards the outer radius mark. 

 

Now build the arches including the barrel and pier inner surface, and glue them in position to the inner radius mark.  Cut a sheet for the outer radius wall, and bend it to fit the outer radius line, holding it temporarily in position (the awkward, sweary, bit), and when you've got it to stay put, mark along the inside of the piers and tops of the arches.  This will give you the marking to cut the outer wall arches.  Finish off with facing, lots of fun with brick arches and keystones, brace it internally or fill it with something like insulating foam for soldidity, and cut a piece of card for the trackbed, which will hold the foam in.  Then upper walls or railings, maybe buttresses and you're ready to lay the track on it and ballast.  Include potlog holes where the wooden scaffolding would have been positioned while it was being built, and drainage holes.  If you don't want to use brick or stone paper or sheet, I'd skim it with modelling plaster and scribe stone block or brickwork into it.  Save time by making a set of stone block shaped loops of wire to impress into the plaster before it dries; these can be used in different orientations and are great fun!

 

If you want to be really clever, you can include revetments for refuges or signals, different shapes for junctions as you come off the viaduct, or smaller/larger arches.  The advantage of scratching it is that you can build it 'bespoke' to fit it to the site, and incorporate transition or other curves if you want to, multi-track widths, any height you like, arches at angles, and you can have it on a gradient if you like as well.

 

You've got me wanting a layout with a viaduct, now...

Edited November 30, 2022 by The Johnster

[JZ]

Now I'm home, I found a couple of pictures that show the curve. It's probably about 6'-7' radius.