The whole lot is mounted on the good old standby, tights packet card. I needed to do this as being a skew bridge I had to set the angle out. First time I've used a protractor since I left school. And no it wasn't made of slate. So, mounting card 65mm high built to make a crooked box and covered on two sides by Slaters brick plastic.
A little banding added to break it up visually and painted with Brick Red, Scorched Brown, Pale Grey and Multiple Unit Green
Balanced to check. Girders painted Brick Red, followed by Leather. Washed over with Black and then covered in talc just before totally dry. Everything either Humbrol or G**es W******p acrylics. There's a fair bit to do yet and its' worth pointing out that this angle of view will be impossible when finished... unless you have a very small head.