The K-Zone: A G-scale garden railway: what I've learned

Things that worked

• The method I adopted for constructing the trackbed -- building a bed of coarse grit mixed with cement, and then dampening it when the positioning is correct -- seemed to work really well. The track held its position very well throughout the changing seasons, and needed very little maintenance. The rigid fixing meant that the track was easy to clean, and I could use a stiff brush to sweep off the dead leaves and cat poo. The mounting proved to be quite strong enough for children to trample all over without ill effect.
• On reflection, I'm glad I didn't go to the trouble of soldering jumper wires across the track joints, or clamping them together, as it would have been a wasted effort. A dab of graphite paste worked perfectly well, and we never had any problems with continuity. However, our total track length was much smaller than most garden railways, so this isn't an enormous surprise.
• The relatively inexpensive LGB loco and coaches survived a whole winter outdoors 24 hours a day, and are still running perfectly well. Young Max wrenched the roofs off both the coaches and filled them with Bob the Builder figures, but that doesn't seem to have affected their operation. Apart from the odd drop of oil, they've needed no maintenance at all.
• The buildings that I finished with outdoor varnish survived both the heat and the cold well. When I dismantled the railway for moving, they came up in one piece, and will be redeployed on the new railway. See below for what happened to the other buildings.

Things that didn't work so well

• Wooden buildings that were simply treated with wood preserver survived the cold weather, but did not survive the hot. In the height of summer, the wood warped. It didn't warp much, but it was enough to break the glue bonds. Some of the structures I finished this way had to be thrown away. Even the most matt of matt varnish has a slight glossy sheen, and this doesn't look entirely realistic. However, it looks a lot more realistic than something that's fallen to bits.
• The overhanging eaves of buildings provide a natural habitat for snails. In G scale, a snail is about two feet high, so a snail-infested building is a surreal sight. The only solution to this problem (or, at least, the only solution I can think of that does not involve cruelty to animals) is to avoid making buildings that are shaped so as to provide a rain shelter for beasties.
• If I could have used curves with a greater that two-foot radius, I would have done. It takes considerably more power to push a train around such a tight bend, than it does on the straight. This fact, combined with the slight gradient to one of my curves, meant that the 1-amp transformer supplied with the LGB starter set was only just up to the job. Sometimes after 10-15 minutes continuous running in hot weather, it would trip and shut down, always at exactly the same spot on the track.
• A plastic rubble sack does not make a good pond liner. After a whole summer, the plastic had become brittle, and would probably not have held water. In any event, surface evaporation was sufficient to dry my one-gallon pond in about two days, so there was never any water in it anyway. Next time I'll grit my teeth and fork out for a proper pond liner, and dig a deeper hole.
• I remain of the opinion that nothing looks as much like wood as wood itself. I am very pleased with how some of my wooden buildings turned out. However, although constructing buildings of modest size (e.g., 8 inches or so to the longest side) is not too expensive or time-consuming, I've found that the time and expense don't scale with the size of the building. As you go from a building that is about 8 inches to a side, to one that is about 16 inches to a side, then the volume of the building increases by a factor of eight -- this is just geometry. So the time and cost don't merely double, they increase four- to eight-fold, as you'll need a stronger and more complex internal structure, and perhaps four times as much exterior wood. In addition, things like doors and windows become large enough to need their own detail, and at this size you have to think about the problems of wiring the interior lighting (if you have it). A building of this size can't be lit by a single grain-of-wheat bulb on a stalk. None of this is a huge problem if you have a few modest buildings on a small railway, but cost and time are likely to be prohibitive on a larger railway if there's just one person doing most of the work and that person has a day-job as well. In short, I have resigned myself to the need to investigate other construction methods in future.

Disasters

• It was a mistake to plant tomato bushes around the railway. Tomatos grow furiously, and in about two weeks in midsummer they had infiltrated the buildings and made the track impassable.
• It was a mistake to use ordinary PVA glue when I ran out of the waterproof variety. If you need your glue to hold together outdoors, it needs to be waterproof. One of my bridges fell apart completely because I used non-waterproof glue.

Things I wish I'd known

• Cats play havoc with bare soil. If there was more than about ten square inches of soil showing, some wretched moggie or other would come and dig it up. I didn't mind the holes so much, as the fact that they'd throw the mud onto the rails. In the end, I cut six-inch lengths from the end branches of an apple tree we were drying out for firewood, and stuck them into every bare piece of soil. They not only looked like trees (albeit very autumnal trees), but their spikiness thoroughly repelled the cats. Hah!
• When it rains heavily, exposed soil shrinks under its own weight. This had the effect of lowering the surface of the soil bed by about an inch after I'd filled it to flush with the brickwork. If I'd known this, I'd have ordered enough soil to top it up.
• G-scale trains are surprisingly tolerant of uneven, dirty, and misaligned track. However, they are not even slightly tolerant of gradients. On my new garden railway, I'm laying out the track with a spirit level to ensure it's perfectly level.