Technical limits
Heights, gradients and cant change the track geometry itself. This page states the rules that follow from that, so a surprising result can be recognized as a consequence rather than a bug.
What the plan stores
In plan view, a track is always flat. Height, gradient and cant are stored as numbers at its ends, and the track is bent in between. It follows that:
- Snapping, selecting, printing and the 2D view all work with the unmodified plan view.
- If the values at two ends don't match at a joint, that's a visible step.
- Raily 4 does not know these numbers and shows the line flat. They are not lost in the process.
Ramps
- Bend the track is the default, because a track piece tilted as a rigid whole cannot hold its gradient through a curve: it leaves a curve flatter than it entered it, flat outright after a quarter circle. The kink then sits at the joint. Keep elements flat exists for compatibility.
- A ramp must have transitions at its ends. Two tracks count as connected when their ends are at most 3 mm apart and their directions match to within about 1°, including in height. Even 2% gradient without a transition is more than that. The ramp editor rounds them off on its own.
- At the upper, free end of a helix, the track keeps climbing at full gradient. Flat track will not snap in there; place a short ramp in between.
- A turnout is rigid. It can be raised and tilted, but not twisted, and it gets no cant.
- Poles and labels remember their position as a length along the track. Because a bent track gets longer, they shift a little on a steep ramp — about 9 mm over 10 m.
Cant
The calculation is tan(cant) = v² / (r · g), point by point, then clamped to the maximum
cant (default 160 mm real-world, converted) and to the cant ramp 1:N. That's why the twist
starts already before the curve.
If a curve is too short for its ramp, it gets less cant, not a steeper ramp. The display tells you.
Helix, tunnel and embankment
A track is a line and may come arbitrarily close to itself. A tunnel, an embankment or a cutting sweeps a cross-section along the line. If the turns of a helix lie closer together than the profile is tall, that solid does not exist, and Raily refuses it. The rise per turn is then to blame.
If a profile is wider than the curve's radius, its inner part collapses. The part goes flat there, but stays usable.
How wide a tunnel is suggested
It isn't the width of the car that decides whether it fits through. In a curve, a long car swings its middle inward and its ends outward, and on model radii that adds up to a lot: a 26.4 m car sweeps out almost double its own width on R1 (360 mm in H0).
Create tunnel… therefore suggests the inside width based on what reference vehicles sweep out at this track's radius. As a guideline, for a 4500 mm wide bore (real-world size, H0):
| Vehicle | from radius |
|---|---|
| Passenger wagon | 725 mm |
| Engine | 235 mm |
| Freight wagon | 190 mm |
| Short wagon | 100 mm |
The number is a lower bound
The calculation assumes a rigid block on a fixed line. It knows nothing of sway, suspension, buffers, footboards, or the gaps between coupled cars, and two tracks side by side each need the allowance separately. If you're building tight, push the longest car through the curve by hand before you pile the mountain on top.
Dragging in the 3D view
A dragged element lands where the ray through the pointer meets the work plane. Near the horizon there is no longer a usable spot for that: the element stays put until the pointer points at a sensible location again. Tilt the view steeper rather than dragging against the limit.
Very thin lines
A line with a width is built as a surface, and that costs more the thinner it is. Imported drawings often come in at 0.26 mm. If you don't need the width, set it to 0: the hairline is always one screen pixel wide.
Catalog data
Manufacturer, sales period, track material and build depth come from catalogs, technical documentation and measurements of real track. Older products are documented patchily, and almost no manufacturer publishes sleeper heights; where they're missing, they are estimated. Hence: to the best of our knowledge, without guarantee. The track geometry is correct; the build depth may be off in individual cases.
If you measure it yourself, you'll know more precisely. We welcome corrections with the track library, item number and measured value at support@enigon.com.