... . They all have a reference point that lies on the plane corresponding with the bottom surface of the timbers. The template is placed on that plane. The various blocks are simply dragged from the Blocks panel and their reference (yellow dot) is snapped on to the template at the intersection of the rail gauge edge and the timber centerline. TurboCAD has a rubber stamp feature that lets you stamp the same block repeatedly with one mouse click. I've used it here to replicate a number of three bolt chairs on the template. 2983_040211_290000000.png Some of the chairs will need to be rotated after stamping them in place. 2983_040211_300000001.png Here one chair has been selected and has been rotated and realigned with the direction of the rail by dragging the X handle and snapping it on to the rail edge. 2983_040211_310000002.png The timbers are extruded to the desired height with two mouse clicks. I have extruded one in this shot but I find it best to position all the chairs before extruding the timbers. 2983_040211_310000003.png To avoid having to make lots of different chairs for all the possible crossing ...