Creating Helix In SCARM – Part 1 – Using Sectional Tracks (VIDEO)

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.

3. Repeat the curve (using Spacebar) to make several rotations, as much as you wish.

4. When ready, select the helix circle (using selection rectangle).

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.

See also
How to create helix FAQ topic

4 thoughts on “Creating Helix In SCARM – Part 1 – Using Sectional Tracks (VIDEO)

  1. Have managed to construct a helix, but cannot print it out with elevations on the track printout because the track from only the highest elevation shows in the printout. In order to construct the Helix I really need to set the track to the correct elevations in order to get the grades correct. Currently everything on the Helix is on Layer 0. Maybe there is a way one can split the Helix into different layers so that the top circle could be peeled off and put on one layer and so on downwards, but I cant work out how to split the spiral. How does one select and move just one highlighted section of track to another layer? The move command doesn’t seem to shift things to a new layer. It only moves things in 2D space.

  2. Thanks very much for all your useful feedback and your excellent program. I have now compiled a layout with a helix and several crossovers all at different elevations – which are great to view in 3D as a complete entity, but when working on the designs are really difficult to sort out what is going on in 3D as currently you have (1) no option to view only the active layers (ie, those ticked in the boxes) in 3D and (2) no ability to print only track from one selected layer (ie, ticked box). Both these options would be a great help in a future update to be able to see only the layers that are “ticked”.

    For the 3D view being able to view one layer at a time would help immensely in designing and planning the overlaps.

    Also when one adds objects at different elevations the track plan cannot be printed without the object obliterating everything. If for example a board is placed at a given elevation and the track is brought up through the board in a tunnel, it would be nice to be able to print ONLY the view above the board – ie, hiding all the Helix and approach tracks that are “underneath” the board. This would also help tremendously for sorting elevations on helix layouts where the ever higher layers of track obliterate the tracks below – so you cant read the elevations to get grades correct. In these cases I have had to resort to screen dumps of individual layer views on the screen.

  3. Hello Trevor,

    Thank you for your comments.

    I will try to make the layers to work also in 3D in some of the next versions of SCARM.

    For printing only the selected tracks/objects, use Copy, then Paste in a newly started instance of SCARM (in a new empty project) and finally print that.

    For the objects that are places always on top and/or hiding other tracks/objects – I will work to make tracks and objects sorting by order in 2D with user commands such as Bring to Front / Sent to Back and Move Forward / Move Back. That should help and will come in some of the next versions of the program.

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