Hi
Probably the easiest method in Sketchup would be to draw the end cross section of the coaches and use the Push-Pull function to extrude the flat surface into a solid of the required length. You can then draw a rectangle on the flat underside of the solid and Push-Pull again to hollow out the interior.
For the beading on the curved surface of the body below the waist, I would be inclined to draw up a "laminate" of the required thickness of the beading (presumably half an inch to an inch) in the same way as extruding the coach body, and then punch holes in it to create a "fret" which can then be attached to the hollowed-out bodyshell. The Offset function should be helpful when drawing up the cross-section of the laminate.
In order to punch the holes, you would need to create some "punch tools" using the same method as extruding the body. To save effort, use the Make Component function so that each tool can be repeatedly used. The punch tool can then be positioned at the required point (ie passing through the laminate) using the Move function. Once in position, right-click on the punch tool (using the Select cursor) and select Explode from the menu that appears. The punch tool will then no longer be a unified component but a series of highlighted lines and surfaces. Select Intersect Faces from the Edit main menu and then With Model from the sub-menu that appears. Sketchup will work away for a bit and the highlighting will disappear. Now, you need to delete all the projecting parts of the punch tool. All that should remain is the outline of the punch tool cross-section on the curved surface of the laminate. Use the Select cursor to highlight the surface contained within the outline and then delete it. Repeat for the surface on the other side. You should now have a hole in the curved surface. If you need more punch tools, select the Components menu from the Window main menu. Once all the holes have been opened out, use the Select cursor to highlight the whole fret and use the Make Component function (you will then be able to load another instance of this component and create a mirror image using the Flip function). Use the Move function to position the fret on the bodyside.
As can be seen, the process is cumbersome but straightforward once one gets the hang of it (I used the same process to punch out window apertures in the curved bodysides of Mk.1 coach bodies). The method is presumably equivalent to Boolean joins in other applications.
