Warning - big rambling post ahead! (including non-standard images which some may find disturbing)
body is pretty much finished - some (very) rudimentary backhead detail (you'll struggle to see much with the crew in, plus it'd be fragile if I drew it properly and likely to be rejected by Shapeways' very inconsistent button pressers.
Steps are printed, but I've put a bit of reinforcing on the back.
Holes for handrail knobs/pipes are put in place, they might need drilling out a touch (better to be a little small than too big) but at least they'll be in the right places and level! The little bit of beading around the cab opening presents a particular problem, especially where it affixes to the top of the cab handrails. My solution is to use microstrip once I've threaded the handrails (0.4mm brass rod) through. It'd be too fragile if I printed it on without the handrail, and the handrail itself would be pretty fragile if printed. I've always left off rivets and handrails, preferring to add them afterwards so you can smooth the surface (seems to be the same conclusion Mr Bedford has come to). Whilst you CAN print everything in place, it'll be hard to avoid breaking small bits off.
I'm waiting on gears and wheels to finish the chassis off.
Paul/John Coffin -I can do transitions and shapes pretty well, but getting accurate drawings is the trick (and photos, if you can find them - often you draw it 'correct' but it doesn't look it, so I try to tweak until it looks right from all angles, the advantage of being able to render the CAD model and spin it around).
Here is a set of 550mm gauge Couillet/Decauville loco fittings (the various transitions on these were as hard as anything I've tried, but they came out beautifully, did these for a friend in the netherlands):
This is my little Bagnall Sipat. The loco is 6cm long in 7mm/ft scale, smaller than the Y7 (its probably over twice it's actual size on your screen)! The finish is good enough for me (looks worse than it is due to the noise from the poor light conditions - roy link's photos in NG&IRM are much better), and the transitions/curves on the chimney and safety valve bonnet are spot on to the manufacturers drawings (I printed elevations from CAD and overlaid them to check):
and yes, I did tidy up the rear bufferbeam afterwards!
The point isn't to show off my previous models - I probably do lots of things the wrong way as I taught myself CAD - went from never having opened a CAD program to finishing Sipat in 6 weeks of spare time, but that the quality IS good enough for models, and that it provides a way to produce prototypes which are obscure enough that they'd never be commercially viable in any other material/medium. Whilst it isn't a mass production method, I have sold over 40 locos in the last year (which surprised me - there aren't many of us modelling 18" gauge), and not needing to keep stock or spend my time casting/packaging is great. It won't make me rich, but it makes my hobby pay for itself without any major effort or time from me.
The Y7 is a different matter, it clearly is a viable prototype (there were 2 kits in production for a good length of time), but I quite fancied one (may have been a delayed reaction from visits to Tanfield/Beamish last year) and I figured I could produce something which others might want as there isn't anything on the market at the minute in 4mm/ft. A bigger loco wouldn't be viable, and as Bill has said, rolling stock would cost the same or more than a loco. In time I expect that the situation will improve.
Anyway, the top bit is done, the chassis just needs a bit of fiddling, but I like to draw my gears/motors in CAD to check they fit and produce a mounting for them. No plans for compensation for now, perhaps in the future I'll have a play.
