How would you model this bridge (culvert) ?

[nickelplate759]

This bridge (or is it a culvert?) is where the NS (nee Wabash) crosses a creek just west of New Haven Indiana.  I pulled this image from Google maps.
I'm trying to figure out how to go about modelling it.  In particular, what materials to use.

I'm reluctant to cast it in plaster, as making the forms seems like a lot of trouble (even if very close to prototype construction methods).  I don't really know the dimensions, so I'm just going for the general feel of this structure.   

If it helps, the back side won't be readily visible on the layout.

Looking for suggestions on how to approach this.

[Mark5]

Looks like cast (poured concrete into forms) - my first thought is to make it from styrene (or similar).

[btrain]

Recently I’ve used Balsa wood sealed with a few coats of diluted wood glue to mimic concrete forms. For the concrete deck, I’ve used Midwest Products Hobby plywood sealed with a spray on dull coat and secured it with mini brass wood screws to the balsa supports.

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[C855B]

I'd cut blocks out of pink foam scraps and slap concrete color craft paint on it, weathering to taste. I'm not at the layout building to grab a picture, but I've done that with a temporary bridge and it's surprisingly effective.

[nickelplate759]

I'd cut blocks out of pink foam scraps and slap concrete color craft paint on it, weathering to taste. I'm not at the layout building to grab a picture, but I've done that with a temporary bridge and it's surprisingly effective.

By coincidence, the (functional and hideous) temporary bridge on the layout is indeed a painted pink foam scrap.

Right now I'm leaning towards styrene - the piers are probably the most work, and really just simple boxes.

[davefoxx]

You won’t like my idea, since you don’t want to build a mold.  But, if it were mine, I’d do exactly that, except that I would mix/pour anchoring cement, rather than plaster.  That’s how I built these abutments under this plate girder bridge:



DFF

[nickelplate759]

You won’t like my idea, since you don’t want to build a mold.  But, if it were mine, I’d do exactly that, except that I would mix/pour anchoring cement, rather than plaster.  That’s how I built these abutments under this plate girder bridge:



DFF

That does look great.  Never heard of anchoring cement.

[MK]

That does look great.  Never heard of anchoring cement.

It's the stuff you use when putting/anchoring a post into the ground, e.g., mailbox post.  It's very dense.  Easily available at any big box home improvement stores.

[robert3985]

If it were me, since the shapes are so simple, I'd construct it out of Poplar craft lumber I buy at The Home Depot in various sizes.

I build all of my tunnel portals and bridge abutments out of either Poplar or premium pine which I cut on my 12" compound miter saw with a fine-toothed tungsten carbide blade, and shape with my oscillating edge belt spindle sander...finishing off the surface with finer sandpaper, wire brushing and small chisels of various shapes.

My UP tunnel portals represent concrete, and it's easy to scribe in the concrete form lines, make cracks and chips, and get a really nice concrete-like finish after painting and weathering with washes and dry-brushing using prototype photos as my reference.

An added bonus for this small culvert/bridge is that making it out of wood, then gluing it in place with premium yellow carpenter's glue, makes it structurally strong and it's not going to crack or break like cast plaster of cement might do.

Works really well for me...

Cheerio!
Bob Gilmore