Component

A component is a list of shapes in its own frame: in the section x runs across (+ away from the centre line on the right side), y up from the insertion point; on the plan x runs along the alignment and y across (+ right). Every value can be an expression of the parameters – W/2, max(T, 0.15), sqrt(1+K^2), if(D>1, 0.2, 0.15).

Polygons are filled with their material and measured; "|" in the points starts a hole (the cell of a box culvert). Circles with an inner radius make pipes. Component inserts another one (a girder in a deck, a sleeper under the rails), repeated N times every Step. Along line draws a line along the whole run on the plan (rails, drain walls, kerbs).

On the plan: Along the alignment repeats the plan shapes every Spacing metres (sleepers 0.6, posts 3); A symbol draws them once at the chainage of a placement (a culvert, a mast, a pole). Mirrored on the left makes drains and kerbs face outwards on both sides; Turns with the slope sets a sleeper on a canted track.