Parametric OS-Railway Tracks - Curve

The rails I have made for my models have generally been wooden which allowed me to make them much longer lengths than would be possible with my 3d printer. However on a couple of occasions I have designed and 3D printed some short rail lengths for displaying the models I have given to other people. Wooden rails are fine, even essential, for animation where long runs are necessary and fine detail isn’t. But for display, the 3D printed rails win with their greater detail. So I was prompted to develop a parametric track model which I could easily use to match my own models as well as other standard scales such as the OS-Railway system or the garden railway scale. I suspect it may be tricky getting a good print for smaller scales such as HO, but the parametricness will still work down at that scale.

You can find a more detailed explanation of this project on my website.

The General Parameters

• RailHt = Height of the Rail
• TrakGage = Track Gauge. This is the distance between the inside edges of the rail head NOT the distance between rail centrelines. For The Opensource Railway, this is 32mm. For my narrow gauge models it is 36mm, and for my 1:24 railcar chassis models, it is 60mm.
• SlprLn = Sleeper length.
• SlprHt = Sleeper height.
• SlprWd is the width of the sleepers.
• NoSlprs is the number of sleepers in the section of rail to be produced.

Curved Track Parameters

• CurveRad = Radius of railway centreline
• CurveSegAng = The angle of the track segment being produced. You will need to choose this to suit your printer bed size.

Connector Parameters

The parameters for male and female connector lugs are;

• FemLockD = OS-Railways System Female Connector Diameter. Standard size for this is 8mm.
• MalLockD = OS-Railways System Male Connector Diameter. The standard size for this is 7.8mm

I have found that the tolerance was a bit tight at the standard size so I have the MalLockD default set at 7.6mm. This reduces the fiddling around with a fine file to get it to fit. If you are using a fine nozzle you will probably be able to set this back to the standard OS-Railway size.

NOTE: The standard OpenSource railway track has a 2mm wide rail head width while the profile used in this parametric model has a 3mm rail head width when the rail height is scaled to 6mm to match the standard OpenSource railway track height. Because the connecting lugs are positioned on the centreline of the rails this means there is a ½mm connector position mismatch between the models produced with this parametric model and a standard OpenSource railway component you might pull off Thingiverse. You may have to do a little bit of work with a file to get them to connect if you are trying to connect in a large number of the two types. Other than that they should match seamlessly.

Other Parametric Track Models in this series are:

• Standard Straight Track https://www.thingiverse.com/thing:3400628
• Standard Curve Track https://www.thingiverse.com/thing:3400642
• OS-Railway Straight Track https://www.thingiverse.com/thing:3400784