Modeling Information
Benchwork is the term given to the structural assembly that supports the model railroad layout. In Lynn Westcotts authoritative work How to build Model Railroad Benchwork, he identifies two ways to frame the railroad layout and three ways to support the track.
Framing
Think of framing as the
bottom level of the layout, the basic structure that everything sits on.
The two ways to frame the layout consists of the butt joint framing
method, and lattice framing. Both methods can be 'free standing',
requiring legs and braces, or secured to a wall along one or more edges,
with or without legs and bracing.
Butt joint framing (also called Open Grid) is a one layer scheme consisting of a perimeter frame with crosswise joists. Butt joints are connected with screws or strengthed with corner blocks and gussets. Those blocks and gussets can be either wood or metal. Commercial roof truss construction has specialty structural metal products that have model railroad benchwork applications. Butt joint framing is ideal for layouts that will use a very light weight track support system. See Butt joint framing for construction details.
Lattice framing (also called L-Girder) is probably the most common benchwork type today for large layouts. It is easy to build, lightweight but strong, adaptable to any layout size or configuration. L-Girders are sized to carry the weight of the layout. In HO scale L-Girders are often 1x2s for the girder top rail, 1x3 or 1x4 for the girder itself. Girders can be attached to the wall or can be free standing on constructed legs and braces. The roadbed is either laid on top of the girder assembly (for panels and tabletop), on crosspieces (joists) or on adjustable cleats attached to those crosspieces.See L-Girder framing for construction details.
Shelf
Multi-level benchwork. Multi-level benchwork is becoming more common in recent years as railroad modelers attempt to maximize operations in limited spaces. All the benchwork framing styles can be used. See Multi-deck benchwork .for construction details.
Depending on your layout design will often determine which framing type is needed. In fact, most layouts will have both types. Where the edge of benchwork curves or multiple track levels are needed, L-girder an be used. In the yard and major industrial areas where the terrain is going to be flat, open grid construction can be used.
Track Support
Track
support is the top layer of the layout, the layer that track, scenery
and structures are located. The three ways to support the track is: flat top, cookie cutter and open grid.
Flat top track support. It is a flat surface servicing as a platform for the layout. It offer lows cost, simplicity, little or no construction needed tin many cases and the ease and rapidity of getting ready to build the layout is the big plusses.The flat surface can be wood shelving, wood or metal paneling (such as hollow core doors), plywood or extruded styrofoam sheets cut to size. See Flat top, Shelf benchwork, and/or Panel for construction details.
Panel
Cookie cutter track support.. Similar to flat top, it differs in that the roadbed can be cut with a saber saw to change the elevation of the roadway, or you can cut openings for lower level scenery. Cookie cutter benchwork is often plywood or extruded styrofoam sheet due to its structural strength and can be cut to length and width. See Cookie cutter benchwork for construction details.
Spline Track Support. .
Construction
There are two ways of constructing benchwork: do it yourself (DIY) or purchasing it.
If you choose to purchase there are companies who will sell you completed systems Sievers Benchwork is one of them. The Sievers Benchwork system consists of a number
of different standard sizes of open-grid sections. Sievers advertises their services for those who 'don't like to, or have the time to drive to your local lumberyard and hardware store, buy
all of the uncut lumber, screws, nuts and bolts, plus all of the tools
you would need - tape measure, square, saw, drill, screwdriver, wrench
and countersink - load them into your car, drive back home, unload,
then mark, measure, cut, drill and sand all of the wood pieces, plus
assemble them'. These Seiver modules can be
simply bolted to each other, making the system adaptable to any size or
type of layout. You have to identify the numbers and types of modules you want constructed and Sievers does the rest. They even have a template process to help you identify what you need (and this template is good for those of us who dont't want to purchase).
For those of us who like to, or have the time for, do it yourself, we now have to talk lumber, screws, nuts and bolts, etc.
Lumber Requirements.
Framing.
A majority of railroad model benchwork is built from dimensional softwood, and pine is the variety most often used. Its found in the dimensional lumber section of lumber supply stores. The most common sizes used are: 1x2's for leg bracing, L-girder flanges and risers, 1x3 for joists, 1x4s for Girder webs, and 2x2s for the legs of a bench or table.
There are two problems with using dimensional lumber for construction. First, the lumber is not dimensioned as (for example) a 1x3. While nominally it is sold as a 1x3, its actual size is 3/4 x 2 1/2 inches. This complicates measurement and cutting in some cases. Second, the lumber is sold for framing or rough construction so it is made up of pine or softer woods. So it will probably have lots of knots. Knots affect the strength of the lumber. Third, dimensional lumber is subject to bowing. You don't want bowed or crooked lengths of boards in your benchwork.
While you can purchase dimensional lumber in prime or select grades (at additional expense), some modelers have found that buying plywood panels (usually cabinet grade) and having the plywood cut by the lumber yard to nominal sizes (a true 4 inches for example) can eliminate the cons of purchasing dimensional lumber, especially in quality and price.The key is to identify the proper product for building benchwork.
There are three types of lumber panels: plywood, oriented strand board (OSB) and chipboard / waferboard. Plywood is made from thin sheets of veneer that are cross-laminated and glued together with a hot-press. Oriented strand board is made from logs ground into thin wood strands that are then mixed with wax and adhesive, formed into thick mats, and then hot-pressed into panels. OSB mimics plywood in most respects. Chipboard / waferboard, a weaker and less-stiff cousin of OSB, is a homogeneous, random composition of sawdust and log chips.
In terms of strength and durability plywood is more stable and less likely to shrink, swell, cup or warp. OSB has the strength but when exposed to wet conditions, it's edges has a tendency to swell. Chipboard / waferboard cannot hold much weight, has a limited lifespan and doesn't fare well with moisture.
Steel Stud Benchwork. I do not have any experience with steel studs, other than I've seen them in the local Lowe's and Home Depot stores. I have fnd a clinic done by John Vogler foJames River Division MER NMRA on the subject. I found it most interesting.
Track support.
A majority of railroad model track support structure is built along the flat or cookie cutter design. That structure is suited for: dimensional shelving, plywood, chipboard / waferboard, extruded styrofoam. Spline construction can use plywood, particle board or masonite.
Plywood and OSB.We have talked about the pros and cons of plywood, OSB and chipboard / waferboard in the paragraphs above. Those qualities apply for track support as well. The primary concern with track support is dimensional stablilty, that is, the tendency of the product to sag between joists or cleats.
Plywood and OSB are generally good in preventing sag. The critical dimension is thickness, and modelers are mixed in their preference for thickness, about 50-50 % between 1/2 inch and 3/4 inch. Personally i have preferred the 3/4 inch due to the reluctance to tear out 1/2 inch and redo it if I screwed up.
Dimensional Lumber. Shelving comes in dimensional size: nominally 1 inch by up to 12 inches in width and a variety of lengths from 4 foot to 12 foot in length. Wider widths go to plywood cut to width. Warp and sag may occur with dimensional wood, plastic shelving does not have that issue.
Styrofoam is a reletive newcomer to track support. It come in a variety of thicknesses, 1/2 inch, 1 inch and 2 inch being the most common in 4 foot by 8 foot panels. It is not prone to warp or sag, and is water resistant.
Spline.
Spline roadbed is made by taking several strips of fairly skinny material, standing them on edge, and laminating (gluing) them together to form a solid roadbed. There is little waste here. Another benefit is the beautifully flowing curves and easements the splines form when bent.
Spline is used primarily in areas where maximum scenery and minimum roadbed. Scenery base can be rosin paper, fiberglass mesh (screen material) or cardboard lattice.
The WWSL
Resources
Westcott, Lynn. How to build Model Railroad Benchwork
Wilson, Jeff. Basic Model Railroad Benchwork, The Complete Photo Guide
Koester,Tony. Designing and Building Multi-Deck Model Railroads
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