Catenary Towers, Part 1: Truing Up

A key element of the Old Line Corridor's visual character is its picket of Pennsy-style catenary towers. As previously described here over the past year or two, my imaginary, impressionistic Northeast Corridor catenary towers were primed black and their magnetic mounts roughed in. Some extended holiday modeling time became available, so I used the opportunity to complete my catenary. In the next three posts, I'll show how I how I took the catenary towers on the Old Line Corridor from 'roughed in' to 'more or less finished'.  

First step: ensure that the roofing nails used as magnetic mounting bases are square. Bar magnets placed on the mounting bases were checked with a plastic square. Adjustments to roughing nails were made using a pliers to twist and shimmy the nails into square and level positions.  

At the entry to the Ivy City visible staging yard, the double track catenary tower was too narrow, so I fitted a four track tower instead. This improvisation necessitated carving away some terrain for square and level installation, as seen on the right side of the photo. 

In the time since I primed and roughed in the catenary mounts and towers, many of the 3-D printed towers warped. Not sure if some of the rough, crooked mounts caused this warping, or if the warping is a natural outcome of the characteristics of the Shapeways FUD material in combination with the thin, near-scale cross sections of the main tower structure components. However, the material is responsive to gentle heating. Here is the cross structure of one of the bridges clamped to a scrap of 1x1 hardwood in preparation for heating.

Straightening a particularly badly warped tower cross bridge section using my festively-colored heat gun. I did this completely by feel and instinct, keeping the heat gun moving and 3-4" away from the catenary bridge, with occasional pauses during which I would touch the assembly. When it felt very warm but not yet hot enough to not touch, I stopped the heating and let it cool back to room temperature before unclamping. Nearly all the towers have developed some degree of warpage, in either the horizontal bridge or 'K' section or in the vertical uprights; I straightened only the half dozen or so that showed the most noticeable warping.

Next up: painting and weathering the catenary towers.