Editing a Curve

Editing curved track is like editing straight, except a little trickier.  When you move a curve, or a straight track tangent to a curve, the program adjusts connections points as you drag so as to maintain tangency.  If a curve is tied into a network of straight sections, this can cause quite a bit of movement, and if you attempt to move a curve too far, track can become tangled.

To move a curve:

1. Choose the Edit tool .
2. Click to select the curve to be moved (shown at left).  The curve turns blue.

3. Press and drag carefully.  As you drag, attached straight sections, and curves on the far ends of those, are automatically adjusted (see above center).  If you drag too far, some curves may not be able to stay tangent, and you can end up with a spiral (above right).  If this happens, Edit Undo and try again.

Because of the requirement that curves remain tangent, you cannot drag a junction which joins a curve and a straight.  In the diagram at left, dragging the highlighted point has no effect, because anywhere you try to drag it will cause the tangency to break.