Simple Computer Aided Railway Modeller

A helix in the track route is used when there is a 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.

A new, powerful and easy-to-use tool is at your disposal, intended for the creation of helices, with the ability to be used either flex-tracks or curved tracks. To use it, select a free start point on the plan and then use “Tools” > “Helix…” menu item.

In the tool’s window, select the desired flex or curved track and enter the radius of the helix (for flex-tracks). Then enter the height difference in the “Height” field – use a positive value for going up or a negative value for going down. Then enter the required number of rotations in the two “Turns” fields: the edit box is for the whole numbers, while the drop-down box is for the fractions, where you can select the exit (end) direction of the helix in steps of 90 degrees. In the fields below, you can set the “Direction” (clockwise or counter-clockwise), the “Track supports” for the helix in 3D mode (default is Arch type), and what to be selected (marked) after the helix creation in the last drop-down list – the exit endpoint or the whole helix. At the bottom, you can check the calculated parameters like the startpoint and endpoint heights, the slope percentage, and the height between the levels (this is only a theoretical clearance - the real one is always smaller). If some of these values get over a certain limit, they will be colored in orange (use with caution) or red (may not work at all). If you see a red-colored value, you should consider changing the height, the turns count, or even increasing the radius (which may require the selection of a different curved track). The diagram on the right will show you the entry and exit points with their true-to-plan directions and will give you a basic idea of what your helix geometry will look like. When everything is set, just press the “Create” button and then see the generated helix in the 3D Viewer.

Note By default, the helix will be created as a bridge, but if you wish it to be in a tunnel, select “Tunnel” mode button on the toolbar before activating the tool and pressing of “Create” button.

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.

Note 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.

◄ Home  |  ▲ Top