A Bridge for Drummondville

The Drummondville layout project is needing a decent representation of the local bridge that spans St. Francis River in that town. While several bridges on the market are close enough approximations, they don't capture some interesting features of the prototype, thus I undertook the task of improving upon what I had on hands. Several pictures can be seen on Historic Bridge website.

As a starting point, my friend purchased an already built Central Valley truss bridge. This is probably one of the best plastic kit bridge on the market, but the previous owner didn't do a great job at assembling it. Several members weren't fitted correctly and some dimensions were off. However, given I would bash it, I didn't mind too much the discrepancies.

Left: pristine kit, Right: after solvent cement is dabbed

My first job was to built the Walthers deck bridge spans on each end of the main span. It was a straightforward assembly, but I decided to try a military modeller's trick to add some steel texture to the sruface. On armour models, this trick replicate cast steel parts. However, since the bridge is built from plates, the texture serves to replicate the motley and irregular surface of heavily rusted steel covered in crust of peeling paint.

Steel texture under a coat of brown primer

The technique is simple. Using an old stiff brush, you dabble solvent cement on the surface. It lightly melt the surface and if you are careful enough, the effect won't be too harsh. If you overdo it, you can easily sand it down a bit and add a light coat of solvent to melt down any odd bump here and there. With a coat of primer, the result is quite impressive and gives a materiality you don't get with plain styrene.

When came the time to work on the main span, I only kept the vertical members and removed all the diagonal braces. Drummondville bride is much stronger than Central Valley prototype which is suitable for older prototype.

New diagonal members were scratchbuilt from 0.5mm thick styrene sheet. It certainly was time consuming, but less than I thought. Anyway, I couldn't locate Plastruct or Evergreen shapes that could have fitted the build and there was no point spending money on something I could do.

Intitially, I made the gussets by punching rivets in styrene sheet... however, the sheer number of gussets and rivets needed for the project was just mind boggling. It would never look good and would take a life time. For this reason, I designed my own gussets in SketchUp and fired up the 3D printer. 3 hours later, I had enough parts to completely rebuild the bridge.

Finally, the bridge was primer with Krylon brown primer and painted with several light coats of acrylic paint. Nothing scientific or special, I simply blended various colors together while looking at prototype pictures. Washes were also used and finally, weathering powders were used to highlight some details here and there. Basically, I used the same techniques used on the previous bridge I did.

At the end of the day, I'm quite satisfied with the bridge. It certainly would have been easier to start with an unbuilt kit, but I think it will be good enough for the layout.