Ted's Under House Suspended Layout


Under house suspended layout article
(Too big to be called a vignette!)
Ted Doskaris
Revision GE-B
April 16, 2007

Overall under house layout description:

I built a suspended roadbed system under my house - which is a walk space changing to crawl space as the house is located on somewhat of a slope on a hill. I did not use a formal track plan for the layout.
Before I started to build the under house layout it took me about 3 years to clean up, install 15 florescent light fixtures, and re-do the entire heat / AC system so that most of the ducting was tucked up / between the floor joist bays, thereby affording more useful room. I also add a second access door to the side of the house and built a train storage closet that is now too small!

The under house overall area consists of 3 structural "bays" with the heating / AC system in part of the center (2nd) bay. The layout goes from bay one to bay three via bay 2 and back again in one giant loop that somewhat parallels itself in certain places.
The layout is somewhat utilitarian in nature, and I have begun to extend the layout out doors – shown and described in more detail near the end of this article.

The layout can be considered as a modified "dog bone" that consists of a self contained loop at each end. The overall layout is roughly shaped like a "U" with the self contained loops also serving as loop backs at the end of each leg of the “U”. As such, the layout is essentially one big loop having two local loops at either end - one of which includes a 270 degree circular loop back.

When I first built the layout I started with a complete circle of 10-foot diameter track. This was the basis for the 270 degree loop back. This way I at least had about 31 circular feet of track from which to operate trains on while I worked on building the rest of the layout. Knowing this I had incorporated three Aristo wide radius turnouts in the circle, each straight section vectoring off to other points that I subsequently built to complete the “U” shaped dog bone.  Thus, I only had to cut one small section of 10-foot diameter curve track as a fill-in to complete the circle.
The 10-foot diameter circle with 2 of those turnouts served as the basis for the 270 degree loop back section of my under house layout as I progressed with its construction. The third turnout vector path goes to a track through an exterior wall where it now extends the layout via a beefed up LGB 4 foot truss bridge to out doors that is now under construction.
So far I have about 45 feet of track laid outdoors with the beginnings of a 2 loop helix grade that I am keeping within 3% max. (By necessity I need the helix in order to gain about 3.5 feet in altitude from my under house layout to an upper garden area.)

At present I have about of 180 feet of mainline under house track consisting of somewhat circuitous "S" bends and curves to get around the various plumbing and furnace system. I made use of cardboard templates before building the layout through these areas.  For the main line, the track work consists of minimum 10 foot diameter sections eased with portions of 20 foot diameter sections leading into and out of the straight to curved areas, and the "S" bends also include a straight section of mostly 24 inches.  On this layout I can pull about a 45 car freight train  (all Aristo with metal wheels) which takes up about half the layout's main line track space.)

The roadbed is 1/2 inch thick 5 ply plywood suspended by 1/4 - 20 threaded steel rods. The suspension rod pairs (that are located on either side of the 8 inch wide roadbed but on about 10.5 inch centers) are placed about every 26 inches. I determined the roadbed minimum width of approx. 8 inches based on the 10 foot diameter track and the worst case length car or loco (which is an Aristo 33 inch smooth side passenger car)  to allow for overhang so the suspended rods won't be struck by a train.  
I placed the roadbed 9 inches below the lowest beam I had to clear that I believed to be the worst case clearance needed at the time I built it as it was based on height of an Aristo streamliner dome passenger car. However, since then I discovered the USA brand container cars when double stacked with containers will interfere by about a ¼ inch!

I used inexpensive 1/2 inch EMT electrical conduit that I attached to the underside of floor joists for fastening of the threaded rods thereto. I drilled holes in the conduit for the rod ends to pass through.
I used 1 inch diameter fender type washers with nuts on either side for the conduit attached end as well as the roadbed rod attachment areas comprised of 4 nuts & 4 washers for each rod.  I used a 5th acorn type nut to finish off the threaded rod as a safety item (avoids cutting one's body if you were to bump against those exposed rod ends, AND believe me, I would have done this a 100 times no matter how careful I tried to be.

Under house layout plywood cutout description

The very first preliminary thing I did was to layout Aristo's 10 foot diameter curve track in a complete circle out on my deck. I then measured its actual diameter in several places, averaged the measurements, and then used this value to make a pivotable radius arm out of a long piece of scrap wood.

To see how the Aristo Wide Radius turnouts may be included, I placed them on top of the circle of track as shown in the foreground of the below picture.

I drilled the radius arm for a pivot hole at one end with 3 holes at the other end. The 3 holes being a center hole for the center to center distance of the averaged measured track value to establish the radius, and the other two outside holes to establish the track tie extremities plus some extra.

I then put a 4’ x 8’ sheet of half inch plywood on the ground and chose a pivot point for the pivotable radius arm.  I anchored the pivot end of the arm with a scratch awl in which to pivot around and then proceeded to scribe on the sheet of plywood using a pencil placed at the 3 outer holes as I pivoted the radius arm.
(If the pivot arm is longer than the plywood sheet as it was in my case for 5 foot radius track, I butted another piece of plywood along side for use as a pivot anchor.)
I then used a jig saw to cut out the sections - moving the anchor pivot point as required to get the best material use from the sheet of plywood.

Suspended layout construction details:

My under house layout road bed as attached to the overhead floor joists typically includes the use of 18 inch long 1/4 - 20 threaded rod, each with 4 x 1 inch diameter fender washers, nuts, and an Acorn nut at the bottom to prevent potential body injury. For most applications, the rods are fastened to 1/2 inch electrical metal tubing (aka EMT), and the EMT is fastened to the under sides of the joists typically using 2 inch long # 8 screws. In my  case, the Doug Fir joists in my house (which was built in 1949) are so dense they are almost like Oak is for hardness. So I predrilled them before using the screws.

To reiterate, the Acorn nut is VERY IMPORTANT to use for safety to avoid bodily injury with bleeding if you should happen to bump the ends of the threaded rods.
(BTW, for injury protection from bumping into certain threaded rods, I used automotive type sheathing slipped over the rods. This sheathing is pre slit along its length and is normally meant for wire harness wrap.
You can buy it by the foot. In many cases, I ran electrical wires within them, too, as I use track power and remote turnout controls. This will be seen in some of the pictures shown below.)

Before the suspension rods are installed, I suspended the plywood road bed - when first built - using string hung from nails tacked into the joist sides as a temporarily suspension until the EMT (and - or brackets) and rods are positioned for final attachment.

The below picture shows part of the above roadbed attached to the rods and EMT fastened to the joists. Since this picture was taken, the layout has been extended through the wall for the outdoor expansion as shown behind the Aristo SP Daylight smooth side passenger car.
BTW, Once installed, the entire suspended road bed is very sturdy, including in the lateral direction  - typically requiring only 2 side supports to a wall for an entire area in one of my under house "bays".

The following picture shows an example ot the layout's 1/2 inch thick 5 ply plywood roadbed as viewed from under an Aristo No. 6 turnout. You can see the fender washers and Acorn nuts on the underside wood cross member. I used short length type drywall screws to attach the supporting cross members.

The following 2 pictures show an example of the layout road bed as suspended using the 1/2 inch EMT screwed to underside of the joists. The proper position of the rods and EMT is determined by use of a magnet type level placed vertically on the rod. The level is used twice with the second time being rotated 90 degrees. A marker pen is then used to identify where to drill the holes in the EMT. When drilling, I have learned to use a center punch and first drill a pilot hole with a small drill bit - followed by the larger drill bit.
Also, you must drill each opposite side individually - otherwise you risk busting the drill bit. A flat file will serve to clean any burrs left from the drilling process and a rat tail file is used for any needed hole tweaking when doing the final mounting - again using the magnet level to do the mounting.

Shown below is an example EMT and rod attachment.

A close up view of the EMT as attached to the joist with the 1/4 - 20 threaded rod using the same road bed fender washers that are used to attach the lower wood cross member to the rods.

Another example EMT - rod attachment view.

Sometimes 2 rods can be attached to the same EMT. Also brackets are used for rod attachments if conditions don't allow for an EMT installation.

The following picture shows an example of a long EMT that is common to many rod attachments.
This is in my rail yard area that includes one of the few straight track runs of my layout!

Sometimes other methods must be used to attach the rods. Shown are a variety of methods - including spacers cut and contoured from PVC pipe that is placed between the EMT and joists to clear objects.

The below picture shows use of a 3/4 inch EMT bent 180 degrees to form a "U" around a furnace duct that was particularly very low.
The "U" is in-turn attached with right angle brackets to the joists.
(Examples of typical underside 1 & 1/2 inch wide plywood cross members can also be seen. Where sections of roadbed are butted together, I used 3 inch wide cross members.)

The below picture depicts an example of using a shelf type bracket to snake through stuff for rod attachments. (I found using such brackets to be somewhat difficult in the way of drilling holes in them since the slots will catch and break drill bits if you need a hole there. I resorted to using a Dremel to help grind the holes in certain problem areas.)

Under house layout experiences:

A long time ago I had a train "string line" on the 270 degree loop back that consists of 10 foot diameter track. One of the Aristo D&RGW 100 ton hopper cars fell about 4 feet on to the cement floor below. (A robust car - as all I had to do to repair it was to CA glue a broken foot stirrup and use a little black touch up paint!)

Since then I added a small diameter stretchable bungie like cord around the inside diameter of the loop back to "catch" anything that may derail. I purchased the cord by the foot at OSH hardware store.

Shown below you can see the protective cord as an Aristo Southern Pacific dash 9 and 2 Wisconsin Central SD45s are pulling a 100 ton hopper car train around the loop back.

When and if I use mid train helper or "pusher" locos on the back of a long train, I plan to install an outside "catch" cord, too.

Train room as some may call a basement vs. my under house layout. What's the difference?

I don't call it a basement because I can't stand up in it except in the taller areas since the floor is not level. To me a basement is a level area that allows you to stand up in it.
Also the floor has "rat proofing" on it which is a very thin layer of cement over the dirt that is intended to keep out any critters that may dig under the foundation.
Though my house was built in 1949 the city codes even in those days required "rat proofing".

Perhaps the picture shown below will provide a better perspective as it shows looking out toward the higher part of the under house area - where I can stand up. This picture - and the next one - were taken in the first "bay" under the house.

The below picture shows looking from the other direction as the floor space becomes a crawl space.

The below picture was taken in the third "bay".
The train closet that is about 10 feet by 5 feet deep is on the left behind the train and bookcase. This is the tallest part which is about 7 to 8 feet tall.

Train Closet:

The below pictures show my under house train closet located in the tallest corner of my under house area.
It includes two 4 foot florescent light fixtures and a pocket door to save space. The closet size is approximately 5 feet deep by 10 feet long by 6.5 feet high. The closet was constructed for potential multipurpose use and built with mostly salvaged materials that I already had, including the use of  2" x 8" studs for one of its walls.
It is fully vapor barriered and insulated from wall to wall and floor to ceiling. It also includes a dedicated, thermostat damper controlled HVAC 4 inch duct. I installed 20 inch deep wire type shelves to hold the G scale rolling stock for best possible ventilation.

In addition to the wire type shelves to hold the G scale rolling stock, I also included a stacked set of drawers salvaged from two work benches.

Outdoor layout extension to date:

My under house layout can be accessed by 2 side doors located on the tall side of house.
The house is on somewhat of a hill. The door opening in the foreground is the one I added prior to building the layout.
The outdoor layout extension is around the corner at the far background end.

Overview of track thus far in place for outdoors looking away from the house. The bricks are temporary.
Presently, about 45 feet of outdoor track is in place for what will become a double loop to gain 3 to 4 feet in elevation whilst  keeping the grade at no greater than 3 percent.

Overview of outdoor track thus far in place looking toward the house.
The trestle in the foreground is the beginning of a double loop.

Bridge attachment point for track going away from the house.
This section is suspended from my deck.

I chose to use a removable bridge to span the area in front of my air conditioner (AC) compressor so it may be serviced or removed if needed. This picture shows access to the under house layout via the small (closed) door as seen on the right side whilst the left side is the bridge attachment point that was shown in the prior picture.

The plastic bridge is an LGB brand that spans nearly 4 feet. I can install or remove it when I want to.
I reinforced it with 1/4 inch thick steel inserts installed at the lower side girder area recess on each side for the full length of the bridge. I painted it with gray primer to match the plastic bridge paint. Aristo stainless steel track is screwed to the bridge.

The portal to bridge and outdoors as seen from the under house layout.
The Aristo Wide Radius turnout is located within my 270 degree circular loop back when under house train operation is being used.  When in outdoor mode as shown in this picture - part of that loop back is used in the reverse direction in concert with a crossover pair of No 6 turnouts located up stream from the loop back.

The below picture shows the bridge head installation as seen from the under house portal.
I chose to use all brass track under the house but only stainless steel track outdoors.
I also placed a re railer at either end of the bridge. Since I use track power, I use switch controlled power wiring to the outdoor layout section. The bridge receives its power from both ends by sliding the standard Aristo metal rail joiners to connect to the adjacent re railer track sections. The rail joiners are not screwed in place as their friction fit is sufficient for providing track power on to the bridge span from both ends. The bridge is also held in place with plastic screw down knobs at each end  (The knobs were obtained from an old battery powered lantern.)

Removable, steel reinforced LGB bridge as shown installed in front of the AC compressor.

A 42 car 100 ton hopper coal train - emulating the joint operation of SP and Wisconsin Central - is shown leaving the under house portal via bridge to outdoors.

The train is traversing the steel reinforced LGB bridge.
(Added insurance that the 16 lb Aristo locos will not cause any undesired stress.)

The train is shown emerging out from under the deck.

Train on outdoor track as far as it can presently go.
(About half the train is still in the under house layout.)

The platfrom structure seems large in area, but it will serve to hold the second loop trestle farther out from the shown loop.

Train at end of trestle for start of first loop with more trestle construction to eventually follow.


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