The K-Zone: A G-scale garden railway: laying track

Note: Since I recently moved house, work on this railway, and these pages, has ceased. I am currently working on a new G-scale railway, taking into account what I learned from this one.
Most garden railways use 32mm or 45mm gauge track (that's 32mm or 45mm between the rails). Track in this gauge has certain advantages over indoor (OO or HO gauge) track. First, it's much stiffer and heavier. This means that if you lay it out on a bed of soil it will tend to hold its shape without much additional support. Second, the larger rails make electrical contact between tracks more reliable (of which, more later). Third, it looks much more realistic, as the height of the rails is more to scale (Peco 100 OO-gauge track has rails that would be a foot or so high in the real world). There is one significant disadvantage, however -- cost. 45mm track is about ten times the price of OO track. This means that it's too expensive to build a layout by buying a big selection of track pieces of different sizes and shapes, then laying them out by trial-and-error. Much more careful measurement and planning is required. In addition, it's much more difficult to bend garden track to shape.

There are various techniques for forming the trackbed. At a pinch, you could just not bother. The track will hold together perfectly well on a soil bed. There are three problems with this. First, it's not very realistic. Second, garden trains are heavy, and the track will deform under the train's weight. Over time this will wear out the electrical couplings between the rails, unless you've soldered them. Third, weeds will grow between the rails.
      There are a number of well-document techniques for making trackbed, and the one to use will depend on the amount of track you have to lay. For large layours, one possibility is to make a trackbed out of inch-thick styroform, cut to about an inch wider that the sleepers. Styrofoam sheet is cheap, easy to cut, and mostly weed-resistant. If you paint it grey, a bit of gravel sprinkled on top will look reasonaby realistic. An alternative is plywood, again cut to shape and layed under the tracks. This will need to be treated with wood preservative before painting.
      Most people prefer to use an all-gravel trackbed, like real railways do. Dig a shallow trench under the rails, and top it up with fine gravel. Lay the track on top, then add more gravel. The stuff we use is B & Q `coarse grit', which costs about £5 for a 20 kilo bag. The gravel you use has to be irregular and rough so that it grips itself and the sleepers. Pea shingle is easier to get hold of, but doesn't work at all well because the stones are rounded and smooth.
      On my layout, I used coarse grit mixed with cement in a ratio about 20:1 grit to cement. The cement has three effects. First, it roughens the grit so it grips better. Second, it makes the grit a more realistic grey colour, rather than the original brown. Third, it binds the stones together when it sets. The cement dust also takes the shine off the plastic sleepers, which is a bonus. The final effect is shown in the photo below.

The use of cement and gravel allows the track to be elevated above the soil bed, again as in a real railway. This is handy for producing shallow gradient, as in the approach to the bridge in the photo below.

There is a great deal of debate about how to maintain electrical connectivity between the sections of track. Unlike 00-gauge track, 45mm track is difficult to solder. It requires a great deal of soldering iron action to get brass rails up to soldering temperature, which usually has the effect of melting the sleepers. It's probably better to solder jumper wires across the track joints rather than soldering the rails directly together. This is because the garden is likely to be subjected to large temperature swings, with consequent expansion and contraction of the track.
      For small layouts like ours, a block of graphite paste in the gaps between the rails seems to do the job.
      However, the balance of opinion seems to be that the best approach is to join the tracks with screw-down rail clamps. These are quite expensive, but appear to offer a permanent solution. The clamps are designed to have the screws hidden in the ballast, so they don't look too ugly.
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