Bridging that gap...

A few different 4mm scale bridges, all following a roughly similar theme, but with variations...

A customer had wanted a scenic divider on his layout, from the station to an area of countryside beyond. There were three tracks, and I will show you the original sketch I made a while ago to give you an idea of the area I had to play with.  After much discussion, many of the features were changed (including the track plan!) but the sketch was a good vehicle to promote discussion about what was needed. The girder spans turned into an arch and a girder, but the flyover configuration was roughly the same.

 

The first thing to do was roll the eyeballs over that trusty and invaluable tome, "Bridges for Modellers" by L. V. Wood. I'm very grateful to Geoff Forster for drawing my attention to this- it is an essential reference work. I figured that I would mix up the spans, making it appear that one was older than the other and I found some plans in the book that looked perfect.

I drew the elevations onto 3mm foamex...I must say here that some folk have told me about the difficulty of obtaining this material, especially if you only want a small amount. (although you will be surprised how much you go through!)  If I can't get an order from 4D modelshop, I have found a number of suppliers on Ebay who sell the sheets in A3 sizes quite reasonably. It's not Palight, but it is good enough for all but the most exacting work. One of the suppliers is Sign Materials Direct who usually have quantities of board available. Be careful to search for "Foamex" or "Palight" and not "Foamboard", which is the card and foam sandwich board. If SMD don't have any in stock, there are plenty of other suppliers on Ebay. Oh, and "XPS foam is also available, but that's not what you want either!

The 3mm board is ideal for civils like this, intrinsically strong and yet fine enough to bend and carve. It was a straightforward job, scribing the stones, if a little tedious at times. John, my customer, had sent me a piece of foamboard marked with the tracks, so I knew I had to follow this for critical dimensions. I overlaid the different levels and heights of courses, finding that the foamex is a delight for producing bevelled or chamfered stones, as on the buttresses and bastions. Of course, with the best will in the world, things need tidying up, and good old Milliput comes in very handy here.

 

Incidentally, the arch of the bridge was made by scribing the top of the arch every 5mm. The  underneath was similarly scribed, then the section was carefully dipped into a bowl of hot water. I left it for a minute or so and then carefully retrieved it, bending into shape and fixing to the arch, taking care that the join was even.

Disaster Strikes... inevitably

So, everything was going fine and dandy until I offered the girder section up to the main bridge. A quick look at the template...and guess what?  I discovered a discrepancy. Try as I might, I couldn't work out how it had happened, but the bridge was curving too much. After leaving it overnight, I decided the only thing to do was to saw a section out of the bridge like a slice of cake (Coffee and Walnut, please) using my trusty junior hacksaw.

I marked where to cut and started sawing. Despite the bridge being built up of many layers, with care, the material cut evenly and easily. I was left with a little gap on one side which I easily filled with Milliput.

The girder section of the bridge was simple enough. I bought some Wills "Varigirder" units which were ideal...and a lot faster than applying rivets by hand.

 

Painting 

Once all the ramps and abutments were completed, it was time to apply the paint. As the local stone is assumed to be igneous, I started off with an all-over coat of Humbrol acrylic 27 which gives a good base before adding effects. I coloured a few stones here and there with warm grey gouache and also some Humbrol acrylic 64. When all was dry, I went over the lot, a bit at a time, with some full strength "Crafter's Acrylic" antique white, dabbing it off again just before it dries. This leaves a nice residue in the mortar courses and generally tones down the walls to a lighter hue. Then it was a case of applying weathering powders and light washes of various greys until I was happy. Sometimes, I applied a lighter grey with a sponge, which gave a great feeling of texture, although care had to be exercised with this or it began to look a bit "samey".

And there we are. All the bridge needs now is a road vehicle crossing, an old North Western "Tiger Cub" perhaps...

 

You might have noticed that the two shots above are of a different bridge, one I made for different customer. Similar construction methods, except this was in Wills stone sheet. That gives a nice result for sure, although it's difficult to get the courses to line up without wasteage. However, at least you don't have to scribe every stone! 

This girder section was made from .030" styrene with the now defunct Archer rivets applied. I did see that rivets were available somewhere else, but right now I can't remember, sorry! Painting was by applying washes of acrylic rust and gunmetal over a dark oxide coloured base, then dabbing the paint off with a kitchen tissue until things looked right. It's a long process, and difficult to judge, but you might well be better at it than me!

Now, below are a few shots of yet another 4mm scale bridge, different altogether, made out of Wills stone sheets again. This incorporated pedestrian steps down to a platform, which I also built. Fairly straightforward, except for the steps.

Lastly, here's a shot of the steps under construction, which were made from two layers of 2mm greyboard.

The white areas on the stonework are where I've used Milliput to fill in cracks. There we are, probably way too many bridges, but I hope at least some of the description has been interesting!