W turns the track (about its middle or the selected end) and a selection of tracks, the joined tracks follow.
E lengthens the track at its free end: a straight stays straight, an arc keeps its radius, cant and grade.
The gizmo on a control point moves, turns or lengthens the vector; the control point of the track joined
there turns with it, at a switch the vector only slides along the switch. Straight neighbours dragged along
keep their tangents and become straight again when nothing bent them.