Laying track in a helix is no different than anywhere else on the railroad. Simply follow the centerlines laid out on the subroadbed. If you choose to use roadbed or integrated roadbed tracks, be sure to calculate that into your vertical clearances. It is easiest to lay track as you go, completing one turn before adding another over top.
A helix is a natural place to use flex track. Not only is it easy work as you lay a constant radius through the helix, you can add smooth easements as you transition in and out of the spiral onto the rest of the railroad.
As with all track work, take your time and test everything as you go. The tight vertical clearances in a helix can make maintenance a challenge once the next turn is in place. While checking the track, use some of your longest cars and check side-to-side clearances as well.
Check clearances against the supports for upper turns and against ajacent tracks. For checking track-to-track clearance, put a long car on each track and push them along with the end of the car on the inner track next to the center of the car on the outer. Using a few extra cars as handles will help ensure an accurate test.
Most helix track will not be seen, so painting, superelevation and ballast are normally not necessary, at least on most levels. If you are building a helix with higher clearances or finished scenes however, simply follow the same techniques used on other tracks.
