Building Down
ARE Headquarters Construction

Click any picture for enlargement.

General Plan

Vienna was built using L-girder benchwork, risers, and subroadbed plywood stringers, many of which came from a sheet of .5" plywood using a sabre saw cookie-cutter operation ①. As shown, this left several large gaps, or holes, for future imaginative scenicing ②. I decided to build a new headquarters building for the Abrams Railroad Empire.

The construction took advantage of these openings to build down as well as up. I don't think I've ever seen an excavation on a model railroad, so that's what I decided to add! The excavation and construction was built separately and inserted in the hole. I built a removable box to fit the hole, including a switch machine that intruded ③.

Research

There's a lot of construction activity these days. I could see several building projects on my commute to work, without going out of my way.

Those sites gave me ideas about the visible components of contemporary construction. I used search engines to explore construction projects from the 1950s, but the most striking aspect came from my memory. I have a vivid memory that construction sites used old doors to make a wall around the site. I think I remember peeking through keyholes to look at what was going on inside.

I Googled "fence made of doors" and found several examples ④ that confirmed my memory. The pictures gave me some ideas what such a wall would look like. I continued Googling individual old doors and collected images of all that I liked. 

I lined up all the doors to get a head-on (perpendicular) view ⑤. I used PowerPoint, but I'm sure that drawing programs would also work.

Wall of Doors

Constructing the wall of doors posed a problem: what material could I use that would be visible from both sides and wouldn't be too thick? Fortunately, I had used aluminum trim coil for backdrops and had sufficient cut-offs for this project. The trim coil is 0.021 inches thick, which works out to 1.8 scale inches thick in HO. That was a pretty good thickness for my doors. 

In PowerPoint, I flipped the image along the top edge. I positioned the original and flipped image so that I could paste both sides of the wall of doors to the trim coil. I used a glue stick to attach the images to the trim coil. That also accomplished having a finished top edge, which changed color from door-to-door ⑥. The height was cut so there was enough aluminum to attach to the sides of the opening.

The Homasote sub-roadbed usually didn't align with the plywood substrate, so the aluminum wall was cut so there was about a half-inch for attachment. I nailed the aluminum to the edge of the Homasote. The bottom edge of the doors should align with the surface of the Homasote. I cut the aluminum so that it was exactly the length of each side of the construction. Figure ⑦ shows doors installed on three sides of the hole. One wall was modeled as a chain-link fence so that the construction crew could have a clear view of the site.

It's obvious from these pictures that the wall of doors is the edge of the opening. But we want the illusion that the ground continues past the wall a few scale feet until the edge of the excavation is reached. That illusion is created when we add the ground after the separate construction is inserted.

Retaining Walls—Shoring

Another important detail is the "retaining wall" around the excavation. This wall keeps the earth from tumbling into the excavation. I learned that "shoring" was the proper term for these "retaining walls" and that the style I was interested in modeling was "soldier pile shoring." Soldier pile shoring is an assembly of vertically oriented steel H-beams placed every six to eight feet on center in a straight line, referred to as piles. (The Soldier beams are called H-beams, rather than I-beams, because the flange is much wider. In cross-section, the H-beam looks like the letter H on its side, while an I-beam looks like an upright letter I.) Wood boards, referred to as lagging, span horizontally from one wide flange to the next and the entire assembly holds back earth on one side allowing a vertical cut on the other. Pairs of soldier beams are driven to a depth slightly below the final excavation. The lagging timber, which is slightly shorter than the spacing but on the order of 2 to 4 inches thick, are installed behind the front flange to retain the soil as excavation proceeds ⑧.  I used the picture of a prototype construction site as inspiration ⑨.

It isn't feasible to construct model soldier pile shoring following prototype construction methods. I had to come up with a different technique. I used Evergreen Scale Models (plastic) H-Columns .125" part # 284, retail 3 / $3.59. To represent the lagging, I used basswood scribed sheets from Mt. Albert, MA723P12, 2 pieces 1/16" thick x 4" x 12", 0.125" = 1/8" scribe.

I reversed the roles of the lagging and columns. The basswood sheets provide the structural integrity and the plastic simulates the steel columns. The general idea is to show enough of an H-column at the top of the lagging to convince the viewer that the column continues all the way down, when in fact most of the H-column has been cut away and only the surface flange remains. I call these "false-top H-columns." Picture ⑩ shows an unmutilated H-column (A), a column where only a half-inch of H retains the T-shaped part is partially cut away (B), and the resulting H-top and flat false-front when the T part is completely removed (C).
Picture ⑪ shows a notch cut into the top board of the basswood, into which the stub H-column is inserted. When the basswood is put in place, only the top of the H-column is visible. The viewer believes that the flat part of the column down the front of the basswood lagging has the rest of the H hidden by the earth it is holding back. The columns have been painted oxide brown.

Building in A Box

Modelling the construction site in the layout was never considered. It was destined to be built away from the layout and installed when ready. I made a box to fit the opening ③.  As you see, the box was built from a repurposed appliance container; I think it was a microwave.
The box had to be odd shaped to fit the opening. Unfortunately, a switch machine mount had intruded into the opening space, which I had to work around. I also had to provide a base in the benchwork to support the box. When I first made the box, the sides were higher than the surrounding ground level, but that got trimmed away.

Picture ⑫ shows the project inserted in the layout for a test fit. A few beams have been painted; but lagging has not been installed. Compare this view with when painting and lagging are complete. In this view soil has been added inside the retaining walls. shows how the soil inside and outside the fence completely obliterates the out-of-site construction.

Picture ⑬ shows the project ready to insert in the layout. This picture was taken after the steel was painted and plaster was poured to simulate the concrete foundation. Also notice the back of the retaining wall. H-columns are used to join pieces of basswood (D and E), while the backs of the false-top H-columns can be seen to go down only a short distance. In this view soil has been added inside the retaining walls. The illusion is complete when soil is added outside the lagging. Picture ⑭ shows how the soil inside and outside the fence completely obliterates the out-of-site construction.

Crane

Tower, or hamerhead, cranes mark all major construction sites. They arrive at the construction siReturn to top   te on 10 to 12 tractor-trailer rigs. The crew uses a mobile crane to assemble the jib and the machinery section, and places these horizontal members on a 40-foot (12-m) mast that consists of two mast sections. The mobile crane then adds the counterweights. The mast rises from this firm foundation. The mast is a large, triangulated lattice structure, typically 10 feet (3.2 meters) square. The triangulated structure gives the mast the strength to remain upright. To rise to its maximum height, the crane grows itself one mast section at a time! The crew uses a top climber or climbing frame that fits between the slewing unit and the top of the mast.

The design of hammerhead crane evolved first in Germany around the turn of the 19th century, The "hammerhead", or giant cantilever, crane is a fixed-jib crane consisting of a steel-braced tower on which revolves a large, horizontal, double cantilever; the forward part of this cantilever or jib carries the lifting trolley, the jib is extended backwards in order to form a support for the machinery and counterbalancing weight.

In addition to the motions of lifting and revolving, there is provided a so-called "racking" motion, by which the lifting trolley, with the load suspended, can be moved in and out along the jib without altering the level of the load. Such horizontal movement of the load is a marked feature of later crane design.

Kibri offers a plastic kit of a yellow Construction Crane # 10202 ⑮, which appears prototypical of tower cranes I’ve seen on construction sites. The kit consists of twelve unique sprues, some of which are duplicated. All the sprues are illustrated on one A4 sheet, with each part number shown. There are eighteen assembly steps, each separately illustrated, showing how the parts fit together. These illustrations are 99% wordless. The part numbers are shown; you have to tediously search the sprue illustration to find which sprue the parts are on. At the end of the assembly process, the crane does indeed look like the illustration.

Finished