This one is gonna be a doozie!!! Warning to dialup folks, this is image-heavy! The prototype: OK, I started late last night, and as of today, I have the basic caboose structure done. It really looks neat, and it's not painted yet!!! From the top, here's how it came from a basic Montana Rail Link caboose to be a Great Northern X1-X30 series slant-cupola caboose. Start: Stock Atlas caboose, std. cupola Chop it up, add a .015" styrene inner frame--cobble it back together for the off-center cupola: Test-fit a side: (.015" styrene sheet) Modify the cupola, by filing a slant onto the ends, and opening up the windows: Lay a chunk of masking tape sticky-side-up, and secure it to the work surface with another piece of tape on each end--this makes holding the sides for window cutting extremely secure! Start cutting blank sides, and cutting the windows into them as well: Drill 1/4" holes in the caboose body, (and hog out holes with file) for the windows, fill in the major gaps with .040" styrene to add rigidity: Glue on sides, allow to dry, and fill in gaps between roof and side edges with putty: *don't glob it on like I did!* Cut a pair of pieces on .015" styrene to fit behind and in front of cupola, file to fit, and using same operation as for the sides, cut in the cupola windows. Glue in, and putty the gaps as before: Starting to look amazingly like the GN X3 picture I posted in here, eh?