How to Build Garden Railway:
Spline Construction Method

In 2016 I finally have the opportunity to build a garden railway. With a 15-month-old grandson I figure I have at least one year to get something up and running. Permission from my wife was a lot easier, too.

After considerable research I decided to build above ground using the spline construction method to support the G scale track. At first I intended to use HDPE composite material but it is very expensive and hard to find. It is similar to materials like Trex that is used in deck construction but lacks the wood fibre making it extremely flexible. There are some excellent articles on the Internet if you choose to go this way.  See the following link for more info from the article by Paul Race in Family Garden Trains about flexible HDPE roadbed:

http://familygardentrains.comprimer/roadbed/ladder1.htm

We used his cutting method as our guide.

I didn't like the traditional method of digging a 6-inch trench and floating the track in gravel.  Too much physical labour involved for my old back and muscles.  With the spline method much of the work can be done in the garage or on the driveway with the work up on saw horses.

Cutting splines

splines fro garden railway sub roadbedCutting splines and blocks for the sub roadbed

Our first step was to cut some splines from 8-foot 2X4 exterior grade lumber.  My friend, Bill Payne, is helping me with this project. His son has a workshop with a large cutting surface. This made it far easier to rip the splines that are about 3/8 inch wide. It is a two-person job. Bill cut as I stood at the far end of the table to help guide the wood. The remaining centre piece of the wood (2 inches) was kept for cutting 1- and 2-inch block spacers and about 2-feet of the pieces were retained to be used as posts. The sub roadbed was wide enough for the rails to sit above the splines.

Making a jig

making a jig for spline roadbedMaking the R3 curve jig

 Our next step was to create a jig. To do this I bought a 4 X 8 sheet of 3/4-inch exterior grade plywood. Using sections of LGB R3 radius curves we laid out the inside edge of the curve on the plywood and screwed in blocks to mark the line. These were spaced about a foot apart. In the photo the clamps are holding the first spline to these blocks. We then glued and screwed the spacer blocks 1-foot apart using 1 1/4 inch exterior screws. We pre-drilled for the screws to avoid splitting the thin splines.

clamping spline blocksCloseup of spacer blocks with second spline

The second spline was glued and clamped to the first spline. We were interested to see if the curve would hold its shape when the glue had dried.

clamping spline curve for a garden railwayClamping the first R3 curve

We had decided to start with an R3 curve that makes a circle of approximately 8-feet diameter. We were interested to see how far the splines would bend. I already had some sections of track from my earlier indoor garden railway. I also have some sharper curved track but will hold that back for sidings. Incidentally, the sheet of plywood can later be cut to build a shed for storage of the trains or to hold sidings so nothing will go to waste.

garden railway spline sub roadbedThe first curved section of spline roadbed

We moved the sheet of plywood with the sub roadbed attached and leaned it against the backyard fence. It sat here for a week or so in both rain and sunshine. When we removed the clamps it held its shape. If necessary, rail can be curved with a rail bender and inserted in tie sections. We'll do this for other sections later when shaping free flowing track.

closeup of spline spacersCloseup of spacers.

In the photo you can see the jig blocks that are held to the inside splines by C-clamps. The 2-inch and 1-inch spacer blocks alternate. Where splines overlap extra blocks can be clamped on for added support while the glue dries. Such a block is visible at the right edge of the photo. We used 2 screws on each side of the blocks. The track sections will be screwed to the blocks, not to the splines. The posts will be hammered into the ground between the splines before the track sections are added. The sub roadbed can be checked with a level and the tops sanded where necessary. The sections have a tendency to try to lift along the outer edge. We would tap the edges down with a hammer and add a vertical C-clamp or even a screw to secure the piece to the plywood base of the jig and this seems to have corrected the problem while drying. I suppose a slight natural superelevation wouldn't be all that bad anyway.

The next step was to remove the sub roadbed from the jig, move it about 5-feet, reinsert it, and then add more spline until we had approximately two-thirds of a circle.  The ends extend beyond the last block and are secured temporarily with a clamp.  We were careful not to align the ends of the splines. They need to overlap for smoother joints. We did this work on saw horses on the driveway and then leaned the jig back against the fence while the glue dries.

building spline roadbed g scale r3 curveExtending the R3 curve roadbed in the jig

First loop

Bill Payne and I finally got back to work on the project at the end of July during the hottest days of the year, of course.

garden railway location of loopThe return loop is hidden under the deck.

After much discussion we decided to put the return loop under the deck and use a lift out section between the edge of the deck and the fence. The track roadbed will be placed on a 2 x 6 inch plank attached to the fence. This will allow me to run a lawn mover to cut the grass. The loop will be sheltered in the winter so there is less chance of it heaving. This area has been stable for a decade.

laying garden railway laminated curveBill is positioning the laminated curve.

Bill came up with the idea of screwing the laminated curve to 2 x 4 cross pieces cut about 18 inches long.  There is gravel under the deck for drainage so it was relatively straightforward to dig out trenches to seat the cross pieces for levelling and stability. We used 12-inch spikes to help hold the curve in place. 

garden railway track cross supportsCross supports are spaced at approximately 2-foot intervals

The sub roadbed was screwed to the supports in the garage and then the track was screwed to the sub roadbed with pan head screws. The ties are screwed into the larger 2-inch blocks in the laminated curve. 

levelling a garden railway curveBill Payne is levelling the curve and spreading the crushed rock user the laminated section.

Levelling lengthwise and laterally is critical.  We used long and short levels. Fortunately there was enough headroom under the deck.

There's nothing like using a test car to check how the track flows. It also makes you realize why you're doing this in the first place!

spiking garden railway curveThe two levels and a 12-inch spike. The spikes at either end of the cross support will help stabilize the curve.
temporary garden railway lift out sectionThe temporary lift out to span from below the deck to the fence.

The temporary lift out is in place and is level to the fence. The ground slopes towards the fence and drops about 14 inches. The 2 x 6-inch board at the fence is held in place by metal shelf brackets. A turnout has been cut in at the fence. The spur will continue along the fence to a small yard to hold trains. More wood has to be added under the curve on the lift out. I used tie sections and loose rail to form the curve to line up with the arm of the turnout. The rest of the track is regular LGB prefab. There is a small kink entering the spur. As I said, this is still temporary to see how things will work out.

Attaching track to fence

g scale track attached to fenceTrack attached to fence on shelf brackets.

We're using 2 x 6 inch pressure treated lumber attached to the fence with shelf brackets. We're hoping this will provide less warpage over the temperature range from summer to winter. This method avoids hammering stakes into the sprinkler system because I don't know where the lines run exactly. It also allows me to mow the lawn. We'll have to use the stakes on the return loop in the garden. 

g scale sub roadbed bracketsShelf brackets with 2 x 4 inch spacer.
g scale sub roadbed splice plateButt joints are secured with 3/4 inch plywood splice plates.

A string was used to set the level for the brackets. The shelf brackets are screwed into the fence boards using the 4 x 4 posts where practical. A 5 1/2 inch piece of 2 x 4 is screwed to the bracket to keep the upper track a little higher than the lower track for visual interest. Plywood splice plates join the ends of the planks to keep the sub roadbed in alignment. The garden railway is effectively a large dog bone shaped loop with the tracks along the fence paralleling each other. I want to avoid a reverse loop.  A passing siding will be added to the lower level when the initial sub roadbed is completed.  The change in grade from the top to the bottom level will be done on the loop in the garden.  Using LGB R3 (16000) track this will result in an 8-foot diameter circle with approach trackage so we hope to keep the grade under 2%.  If it turns out to be too much of a grade we can move the loop and lengthen the approach trackage. This is all experimentation so there is room for changes. If all goes well over the winter we can move the loop next summer and  continue the track along the back 60-foot fence.

I repositioned the string alongside the inside rail and used it as a guide to keep the track as straight as possible along the fence. After rolling a test car down the track to check for clearance from the fence I screwed down the track with #8 1-inch particle board screws. These have a large flat head. I predrilled holes through the ties into the wood approximately every 18 inches. As this was done when the temperature was over 90 degrees fahrenheit (around 30 centigrade) I am hoping that expansion won't be a problem and there should be room for contraction during the winter. We'll see in the Spring!

Our next job is to complete the lift-out sections and install the garden loop. Then we should be able to hook up some electrical connections and get some trains running.  We plan to use trailer hitch plugs for electrical connections. We use these on out club's travelling HO layout and they work well.

Mainline completed

g scale mainline attached to fenceThe mainline is attached to the fence on 2 x 6 inch pressure treated boards.

The mainline runs along the fence. In the photo above you can see one leg to the loop under the deck in the background. 

g scale passing track and loopThe passing track on the lower level.

The grade from the upper to lower track is on the loop by the rear fence. A passing track has been added on the lower track.  I installed it on pressure-treated 2 x 4s. The track is further stabilized by posts sunk into the ground at intervals.  I used a rail bender on part of the loop and at the turnouts for the passing track because I had run out of sectional curves.  Most of this LGB track is "hand laid" by inserting rail into pre-cut plastic LGB ties.  The rail was cut with a heavy duty blade in my Dremel tool.  The mainline is now finished for this year.  I will add a few sidings in the Spring after I see how this construction method weathers the winter.

Now it's on to wiring.

First trains running

g scale garden railway with cn enginesThe first trains to run on my new garden railway (August, 2016)

I kept the wiring simple. Only one track connection beneath the deck. I built a hinged box to hold the transformer and LGB controls. I run some engines as DCC and some as DC using two handheld controllers. The wire to the track goes through a 4-pin trailer hitch plug so it is easy to take the box off and put it in the garage. Only the brown and white wires are currently used. The turnouts are electric but are not wired so I operate them manually.  A small yard has not been built along the fence yet. That's a future project.

I called the layout the Knox Railroad for my grandson (but it's really for me!)

Here's a short introductory video.

First trestle bent

g scale trestle bentFirst trestle bent construction

Bill Payne helped we cut down the leftover boards to a half-inch cross section. I found some discussions on the Internet about wood sizes, dimensions and batter for a typical G-scale trestle. I built a jig to space the bent vertical timbers so they were pleasing to my eye and glued and nailed the pieces with 3/4 inch nails. I made the test bent in March, 2017. I made the bents in the garage on a jig built on a piece of plywood.  I used 1-inch nails and carpenter's glue to assemble the bents and used 3/4-inch nails on the cross pieces. Here's how the trestle looks after the bents were temporarily hung and fastened to the roadbed. The bents don't actually support the track. They are more cosmetic.  The sub roadbed  and track weathered the Canadian winter without any problems. 

g scale trestle bentsThe trestle bents roughly hung beneath the sub roadbed.

Half of the trestle bents are now in place.  The lateral strips need to be added to properly secure the bents vertically but at least it is now looking more like a railroad.

More to come...

This has been my summer model railway project other than building some models for the club's HO layout that you can read about on my NMR page.  If you're interested in how this whole project comes together, check back from time to time or add me to your RSS feed and get instant notifications when I add to this page. You can find the RSS buttons on the right side of this page.

Read about my earlier indoor G Scale layout.

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