Simple Computer Aided Railway Modeller
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How to create helix?
Helix in the track route is using when there is need to get over a big height, which is unable to be realized with simple incline. It can be created with several rotations by connecting same curved tracks together and last point from the last track is lifted to the desired height.
Before you start, check that heights are enabled and are visible on the screen – if not, toggle "View" > "Show Track Heights". Select free point from already existing track in the route and add first curved track of the helix there.
Press Spacebar several times until full circle is formed. Select tracks in the circle, then select the height at the last free point from the last placed curved track and change the height, so maximum gradient reaches 4% - this will show you maximum height than can be get over with single rotation of the helix.
Knowing this value and target height that you want to reach, you will be able to get approximate count of rotations, needed for the climb. Make these rotations (with Spacebar again), select the circle (always with selection rectangle), select the height in the exit helix point and form the final gradient and height of the helix.
Gradient values bigger than 4% are undesirable, because locos will be heavily loaded when climbing, especially with longer trains. Gradient values lower than 3% may be not suitable due to helix support construction or using of catenary. Add last exit track, then set track supports to Arch type (using "Edit" > "Track Supports" menu with still selected circle) for realistic look. You can see the helix in the 3D Viewer and then make corrections in the height or rotations (by adding or removing curved tracks).
Sample pictures are showing helix with final height of 254mm (10") in TT scale (1:120)
The terrain in 3D picture is switched off.
At the moment, there is no sense to Copy and Paste helixes, because when copied helix is joined to another part of the route, the heights of the tracks inside will be equalized and helix effect will be lost.
Creating Helix In SCARM – Part 1 – Using Sectional Tracks (VIDEO)