Sacramento Modular Railroaders

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Sacramento Central Railroad

Serving the transportation needs of the Central Valley of California from Gerber to Stockton with courtesy, reliability and convenience.

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Module Construction

The suggestions which follow are the result of well over thirty years of my experience as a member of the Sacramento Modular Railroaders. I have watched module clubs form and then disappear. Sacramento Modular Railroaders has had active members living over 100 miles from Sacramento who would come as often as they could to one or two-day operating sessions bringing their modules. There are many reasons for their continuing membership - one of them is the construction and design of the modules.

Click on the images below to see a larger image.

General considerations

  1. Size: Modules need to be large enough to accommodate a reasonable amount of track work, with enough sidings and industries to make the train's visit to the module believable. It also must be small enough to fit in the owner's vehicle and light enough to be easily carried. Our standard module is four feet long and either 24" or 30" wide. A very few are 36" wide. A few modules are 6 feet long and either 24" or 30" wide.

  2. Construction: Modules must be sturdily and accurately built. The vertical surfaces (especially the ends) must be accurately perpendicular to the surface of the module (Figure 2). The corners must be square so the module is not a parallelogram (Figure 16). And the length must be accurately the stated length, not an approximation.

  3. Weight: Nothing will keep a module at one's home better than its inconvenience to move it because it weighs too much. So while it must be sturdy, it must also conserve weight as much as possible.

  4. Legs: The legs of the module should be fold-up style (Figure 23) with hinges and 2 folding hardware angle braces per module (Figure 32). The legs again should be light in weight. 3/4' by 1-1/2" legs are adequate joined by a plywood cross brace (Figure 34). Folded legs lie totally within the module side walls (Figure 41). Carriage bolts are used for height adjustment to level the modules (Figure 24).

  5. Height: The surface of the SMR modules is 36" above the floor, with mainline track applied to 1/4" cork or plywood (Figure 2). Most module standards call for a 40" height but since we have had several wheelchair bound members over the years, we felt that the lower height met their needs better and also permitted children to see the operation.

  6. Backdrops: SMR requires a 12" high backdrop made of tempered fiberboard (Figure 50). The backdrop can be removable, but permanent backdrops provide some degree of protection of the module during transport. They also increase the realism of the modular scene by blocking out the clutter that accumulates in the center of any modular layout. They can be painted sky blue, painted with a realistic scene or have commercial printed backdrop attached.

  7. Track: Tracks which interface with other modules are code 100 nickel-silver. Tracks which interface with other non-personal modules terminate perpendicular to, and 4.5" from, the end of the module. The gap allows a standard 9" length of snap track to complete the connection. Turnouts from the mainline are Atlas #6 or Peco large radius for all passing sidings and crossovers. Turnouts leading directly to industrial sidings can be Atlas #4 or Peco medium or small.

    2-conductor polarized connectorTwo conductor polarized connector for joing modules electrically
  8. Wiring: Track power is carried by #18 gauge wire from one end of the module to the other with a 12" dangling drop (Figure 43). Two-conductor polarized connectors (double click image for enlarged view) are spliced onto the wire to join to the next module. AC power for building and street lighting is carried by white 16 gauge lamp cord joined with Cinch-Jones style two conductor line connectors. DCC control wiring is carried by 6-wire phone line with 6-wire RJ-11 modular plugs (All shown in Figure 43). A double female 6-wire connector is used to connect adjacent modules (Figure 46, labeled Santa Falls). All wiring is secured within the walls of the module by velcro slings or by being stuffed into PVC pipe (Figure 44). Loose wires are not desired.

  9. Scenery: Scenery on the modules is a requirement for inclusion of the module in a public show. Foam deserts can be included during our private club operating sessions while the module is under construction. What buildings and landscaping are included are at the discretion of the owner of the module but should be a realistic depiction of what might exist in the real world (Figure 48). Most of our members permanently mount their buildings and have easily broken items, like tall trees or telephone poles removable for transportation.
        Our railroad is truly modular so that any module may fit next to any other module without regard for scenery. Sectional layouts have coordinated scenery and must fit together in a specific squence in order to be complete. When SMR sets up every member owning a module does not have to attend the operating session.

The pictures which follow were taken by one of our members, Paul, to illustrate the construction of the module. SMR has created a jig for making the modules so that they are all exactly alike. The completed units are then sold to the members for the cost of the materials only. They lay the track and add the structures and industries they wish on the basic framework. Figure 48 shows Paul's wife's module, Santa Falls, the theme of which is a Christmas tree farm. It regularly displayed at the California State Railroad Museum in Sacramento. Two additional pictures of Michelle's module can also be seen here.

Enlarged views of each of the following thumbnails can be seen by clicking each of them. After viewing the thumbnail you can click the back button to return to where you clicked.

The basic module is 48" by 30". The construction is designed to be as light as possible. When linked the rest of the modules, they are quite sturdy. 1{short description of image}
The vertical sides and ends of the module must be truly perpendicular to the module surface. Here you can see the marine plywood roadbed glued to the syrofoam and securely attached to the module ends. 2{short description of image}
The legs are permanently attached to the module and designed to fold up within the depth of the module. Each pair of legs is supported by a single brace, shown here. 3{short description of image}
The styrofoam module surface is braced by boards spaced on 12" centers. 4{short description of image}
The two folding braces are attached to the one leg of each pair lying closest to the front and rear face of the module. 5{short description of image}
A spacer block provides a secure attachment of the upper end of the leg brace to the ¼" marine plywood front and rear module face. 6{short description of image}
Each pair of legs is offset to the right at their end of the module so that the leg from the opposite end can lie alongside when the legs are folded for traveling. Note the leg brace on the right leg (#8) of the pair which lies close to the module wall. 7 {short description of image}
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The offset of the pair of legs can be easily seen here. 9{short description of image}
The support cross members are notched before attachment to the face walls of the module to permit layout wiring to pass from one end of the module to the other. 10{short description of image}
The styrofoam is glued to the cross braces. Note the cross brace is inset to allow the legs to fit within the depth of the walls of the module. 11{short description of image}
Overview of underside of module. Note the leg lock on the center cross brace. 12{short description of image}
This simple lock holds the legs against the lower side of the module. See figure 28 for the lock in action. Note there is no spacer block. The lock is flush with the module cross brace. 13{short description of image}
Overview of the pair of legs folded against the module showing the leg cross brace. 14{short description of image}
The leg cross brace is on the inner side of the legs, so that it lies below the surface of the cross brace when folded. Its position on the leg is such that it falls next to the central module cross brace enabling the rotating leg lock to hold the legs securely. 15{short description of image}
The right off-set of the legs can be easily seen here. (The legs at the other end of the module are to the right, as you saw above, in figures 7 & 8.) 16{short description of image}
Detailed view of the legs on the two sides of one end of a module. Note that in Figure 21, the folding metal bracket which locks the leg in the extended position is on the leg which is closest to the side wall of the module. 17{short description of image} 18
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Angled view of the leg with the angle leg bracket. The location of the screws attaching that bracket to the module is critical. The central hinge joint of the bracket must not dig into the styrofoam nor protrude beyond the lower edge of the module wall when the legs are folded. 19{short description of image}
Angled view of the opposite leg. 20{short description of image}
In this view we are looking from one edge of the module to the other and note that nothing protrudes below (to the right in the picture) the lower edge of the module. The module can easily slide into the back seat of a sedan or the back of a van without tearing the upholstery or disturbing the module components. 21{short description of image}
Here the legs are seen as they start to nest. Note how they slip by each other. 22{short description of image}
The legs are in the same position as in figure 22 in this angled view. 23{short description of image}
The leg adjustment screw on the end of each leg consists of a carriage bolt onto which a wing nut is tightly screwed. The wing nut enables the bolt to be rotated without using a wrench, a real time saver. Also note the carriage bolt is screwed directly into the wood providing a tight friction fit which prevents the screw from moving randomly during module transport. Generally, once set, the adjustment screw will not have to bechanged to any significant degree. Note: no tee-nut is used! 24{short description of image}
Here are the legs all tucked into their transport position held in place by the swivel leg lock on the center cross strut. 25{short description of image}
This end view shows the clean lower edge of the module. Nothing protrudes below the side walls. 26{short description of image}
Straight across view. The stuff in the belly of the module is not sticking out to get caught on doorways, furniture or anything else. 27{short description of image}
The legs and their cross braces provide some protection for the switch machines, cables, transformers, battery packs or whatever else might be tucked into the belly of the module. 28{short description of image}
Legs partially folded. 29{short description of image}
Legs extended and locked. 30{short description of image}
This view shows the leg angle bracket from the outside of the module 31{short description of image}
This view shows the leg angle bracket from the inside of the module in greater detail. Note the block of wood to which the hinge is attached providing a solid surface for the upper end of the leg when the leg is extended and the spacer block for the angle bracket which provides a solid surface for the attachment of the bracket screw. 32{short description of image}
Note the block of wood to which the hinge is attached providing a solid surface for the upper end of the leg when the leg is extended. The leg in the extended position rests on the vertical end board of the module preventing it from being over-extended. 33{short description of image}
A ¼" marine plywood brace connects the two legs at each end of the module. The brace is positioned so that its lower edge lies immediately alongside the center cross module styrofoam strut when the leg is folded. It also needs to be wide enough to serve as if it were two diagonal braces. To maintain this position the brace should be both glued and screwed to the legs so that it does not loosen with time. Note that it is on the inner surface of the leg. 34{short description of image}
The cable to carry electricity for track and accessory power passes through the notches cut in the transverse module braces. 35{short description of image}
A 10-wire cable (we found a bargain on 10-wire sprinkler control cable and use that on our new modules) extends the length of the module and at each end of the module is connected to terminal strip. Terminal strips keep things organized and provide a way of checking continuity.

Six color-coded wires carry track power for the 5", 7" and 15" lines and two wires are for the AC accessory power supplied by a large capacity transformer provided by the club. The wires which will be connected to this terminal strip will tucked into the belly of the module. One way is to screw a length of PVC pipe to the end board (two holes, one for the screw, one for the screwdriver). Hook and loop (e.g. Velcro®) , plastic clips or loops, or even spring clothespins can also be used to keep the dangling wires secure during module transport.		 36{short description of image}



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Legs all folded, nice and neat. Dangling wires will be tucked into the PVC pipe. 38{short description of image}
Terminal strips make tracing wires much easier and make trouble shooting a snap (relatively!) 39{short description of image}
PVC pipe attachment 40{short description of image}
Note the clearance of the leg adjustment screw relative to the brace. Also note the transverse brace is narrow enough to permit the leg to lie along its lower edge and still lie within the depth of the module walls. 41{short description of image}
Folding leg brace arrangement. Be sure the leg is perpendicular to the module surface when the brace is locked! 42{short description of image}
This view shows the wires which serve to connect one module to the next on a completed module. Please click on the picture to see an edited enlargement of this picture in which all the wires are identified. 43{short description of image}
Wires neatly tucked into the PVC pipe for transport. 44{short description of image}
How one connects wires between one's own modules is not dictated by club rules. Here Paul has used a multi-blade Cinch-Jones connector to carry rail and AC power. The DCC connection is established using a double female RJ-11 six wire connector (labeled "Santa Falls). 45{short description of image}
Here the C-J connector is closed 46{short description of image}
Paul opted to butt the tracks against one another between Michelle's two modules. Snug fit dowels (peg and socket connection) keep the modules properly aligned. 47{short description of image}
A view of the completed Santa Falls module. It is used for display at the California State Railroad Museum during their model railroading show on each Thanksgiving weekend (Friday - Sunday) 48{short description of image}
The interface for the hand-held cab control units are built into the front and rear surface of every module set so that they are a maximum of eight feet apart. Since the modules can be turned end for end, both the front and rear of the module set must have a connection point. 49{short description of image}
Back drops are essential. They rise 12" above the module surface. They may be plain sky blue or be hand painted or have commerically printed backdrops attached. They make for a much more finished appearing layout. 50{short description of image}
Land forms are created using styrofoam. Use only the blue or pink foam, not the white stuff. 51{short description of image}