Track laying basics for a 16mm garden railway
Good running starts with good track. A loco that derails or stalls is usually telling you something about the track underneath it. Here are the basics for laying a 16mm scale line in the garden.
Pick your gauge
16mm scale models run on two gauges: 32mm (SM-32, representing 2ft narrow gauge) and 45mm. Most of our kits are built for 32mm, and some are available in both. Choose one gauge for your line before you buy any track.
Plan it on paper first
Before you dig or buy any track, decide what you want from the line.
Walk the garden. Look at where you'd like the track to run and where you'll stand to watch the trains.
Choose your features. A station, sidings, a passing loop, a tunnel, a bridge, a quarry for the slate wagons: list the ones you want. Work in the garden's own features too, like a rockery or a favourite flower bed, so the line looks as if it belongs there.
Draw a plan. Sketch the garden on paper and draw the track route with your features on it.
Survey the ground. Check where the ground rises and falls along the route, and find the lowest points. That's where water will collect.
Adjust the plan. Steer the line around the low spots, or change the plan to deal with them. A small pond or stream with a bridge over it can turn a wet dip into a feature.
Start with a solid, level base
Outdoor track needs a firm base that won't sink or wash away.
Ground-level line: breeze blocks or a well-compacted ballast bed both work well.
Raised line, or one you might move one day: a treated timber bed.
Keep it as level as you can, and keep any gradients gentle.
Drainage: cuttings and low spots in the garden are where water collects, so plan for them.
On a ballast base, lay a small perforated pipe underneath to carry the water away.
On breeze blocks, put pea gravel along the sides so the water can drain down and away.
Make sure the water has somewhere to run to, so it won't come back.
If your line has a cutting, avoid making it a dip. We like a steady gradient running in one direction from start to finish, with a way to direct water away from the track at the lowest end.
Flexible track and curves
Flexible track lets you lay smooth, sweeping curves that suit your garden. We stock Peco SM-32 flexible track with wooden-style sleepers in code 200 rail, and G45 flexible track for 45mm gauge. Both come as single lengths or multi-packs at a lower price per length.
Use the widest curves you have room for. Tight curves increase drag and can cause derailments, especially with longer locos and coaches.
Workshop tip: bend flexible track around something with a steady curve, like a bucket or even your belly. Don't push it at one point, or you'll get a kink instead of a smooth curve.
Your smallest curve depends on what you want to run. Small diesel shunters and slate wagons are happy on tighter curves. A Double Fairlie or long trains need much bigger ones. Plan your curves for the biggest thing you'll ever run.
Running two tracks side by side
If you lay two tracks next to each other, at a station, a passing loop or double track, leave enough room between them or two passing trains will hit each other.
The gap is set by your track centres, the distance from the middle of one track to the middle of the other. It needs to cover your widest vehicle, the loading gauge (the biggest width and height your trains reach), plus a little clearance.
On straight track: the Association of 16mm Narrow Gauge Modellers uses 150mm track centres for 32mm gauge on its modular layouts, and allows 75mm either side of each track's centre line. Large stock such as the Vale of Rheidol 2-6-2T is about 135mm wide, so two of those passing on 150mm centres have around 15mm clear between them. That's a good starting point. If you run anything wider, measure it, and keep at least 15mm clear between your two widest vehicles.
On curves you need more. A long vehicle doesn't follow the curve exactly. Its middle swings in towards the inside of the curve, and its ends swing out. Work out both and add them to your straight-track centres:
Middle swing = (distance between the bogie centres or outer axles)² ÷ (8 × curve radius)
End swing = (overall length² − distance between bogie centres²) ÷ (8 × curve radius)
Example: a coach 300mm long, with bogie centres 200mm apart, on a 1200mm radius curve.
Middle swing = 200 × 200 ÷ 9600 = about 4mm
End swing = (90,000 − 40,000) ÷ 9600 = about 5mm
Track centres on that curve = 150 + 4 + 5 = 159mm. Round up to 165mm for a safety margin.
Check with your longest vehicles, and remember that tighter curves need more room. The simplest final test is to push your two biggest vehicles past each other on the curve before you fix the track down.
Joining and pinning
Use rail joiners to link each length. They also carry electrical power through the rails, if you run track power. Check that each joint is flush, with no step in the railhead for a wheel to catch on.
Leave a small expansion gap at each joint. Leave about 1 to 1.5mm at each rail joint, roughly one per yard length of track. Leave a little more if you're laying on a cold day, and a little less on a hot one. Rail grows in the sun and shrinks in the cold, and without a gap the track can buckle and lift in summer heat.
Fix the track down with track fixing pins. These are 14mm chemically blackened steel pins, used to fix track permanently or to hold it in place while ballast sets.
Finishing touches
Ballast makes the line look real and helps keep the track in place. A buffer stop at the end of a siding, or a wagon turntable, adds interest and somewhere for your slate wagons to work.
Keep it running
A little care keeps the trains running and saves you fishing a derailed loco out of a tunnel.
Clean the rails. If you run power through the rails, a track rubber or a cleaning wagon keeps the railheads clean.
Check before you run. Look for debris and any movement in the track. There's nothing worse than the first train of the day derailing in a tunnel.
Check the points. Make sure they work as they should and haven't filled up with muck.
Keep plants at bay. Weeds and overhanging plants can derail trains, or scratch your lovely paint jobs.
Watch the heat. Take care on very hot days. Track can buckle if the expansion gaps aren't big enough.
Winter. If you don't run over winter, bring buildings and other scenery inside, out of the weather. They'll last much longer.
Stan
Comments