Helices in SCARM are briefly described in the documentation at the FAQ topic How to create helix. The following text and videos explains step by step how to create a helix on the layout and how to edit it in order to make it look exactly as you imagine.
1. Select the Start point on the helix enter track. This track should be already a part of the track plan where you want to build your helix.
2. Place the first curved track – select it from the Selection panel.
5. Exclude all the tracks that do not belong to the helix circle (holding Shift key + mouse click over each unwanted track).
6. Click on the height marker of the last placed curve – the selected height will turn red.
7. Adjust the track height (using shortcut buttons, mouse wheel or ‘<’ and ‘>’ keys) to reach the desired height.
8. Watch also the grade marker next to the height one – it should be somewhere between 2% and 3% for curves with larger radii and gentle slope or between 3% and 4% for curves with smaller radii and steep slope.
|Keep in mind that you will need a space for the helix plywood, track ballast roadbed and (eventually) catenary between each “floor” of the helix. To calculate the gauge clearance, you will need to divide the overall helix height (displayed on the track height marker) to the number of rotations. In the video example below we have 3 full rotations and a height of 210mm (8.25″). When we divide 210 (8.25) to 3 we receive 70mm (2.75″) – that is the full space between the floors in which we need to fit the helix plywood base (5mm; 0.2″) plus tracks with thin ballast layer (5mm; 0.2″) and finally for the rolling stock will left 60mm (~2.35″).|
9. When ready, place helix exit track.
10. If you wish, you can adjust the track supports of the helix by selecting the helix circle and applying “Arch” type of supports.
11. Now you can see the helix in 3D. To see the tracks and track supports, you need to either make all the tracks as a bridge (for open helices) or to temporarily hide the terrain (for hidden helices) as shown below.
See all these steps in the demo clip below – creating a helix in TT scale (1:120).
12. If you are not satisfied with the number of rotations, slope (grade) or height, you can edit the helix.
13. To start with editing, remove helix exit track first – this will make the last curved track active, with selected free point at the end.
You can also edit the helix at bottom by removing the enter track.
Remember – do not delete both enter and exit tracks together, as this will make difficult to select the correct start point for editing.
14. To remove curved tracks from the helix, simply press Del key.
15. To add curved tracks to the helix, select desired track from the Selection panel and then repeat it (using Spacebar).
16. Added curved tracks are with equal heights, so the overall helix needs to be recalculated.
17. To alter the height or recalculate the helix, restart the procedure from Step 4.
See editing steps in the demo clip below – editing a helix in TT scale (1:120).
In the documentation it is stated that “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”. However, you can copy/paste and move a helix and you can attach another (flex) track to its base/enter or top/exit tracks. But there is no way for now to rotate the helix without loosing the slope – you will need to recalculate the helix, starting from Step 4 if it is being attached to another part/track of the route.
Get ready for the next article of the helix series which will describe how to create a helix using flex-tracks in the plan.
How to create helix FAQ topic