Single piece chassis version. Probably not flexible enough to insert commercial N-gauge axles but meant to see if my two-piece wheelsets can be assembled in place and work. UPDATE: There is more than adequate flexibility in the single-piece chassis to add commercial wheels. 2mm Scale association wheels on N-gauge sized axles work best. Some old Rivarossi ones with equally thin axles worked too, but some with larger flanges ("pizza cutters") foul the underside of the chassis floor slightly. Disappointingly, Parkside Dundas axles (and some other makes) seem to be too long and bend the axlesboxes and W-irons out, and I don't know why, as my experimental 3d printed ones are based on them so should have the same problem but seem to be OK. Serendipitous loss of length due to slight bluntness of pinpoint, perhaps? Anyway, 2mm society members and anyone with a supply of probably unobtainable Rivarossi N-gauge spares will be fine. I have yet to try bronze axles-bearing cups, or brass hats and shorter axles. The model is very light though, and this may cause you problems if you run them unloaded, in long trains with heavier or rough running wagons behind, or on sharp curves. FURTHER UPDATE. 2mm Scale Association wheels of code 2-007 (3 hole disc, used to be 2-207) and 2-012 (8 spoke, used to be 2-211) work with a little cleaning out/enlarging of the axle box sockets to take the 14.8 mm axles. Mathieson Models 8 spoke N gauge wheels also work, so code 2-014 (8 spoke on 14.2mm axles) or 2-017 (8 open spoke) might be even better. Brass top hat bearings and the old bronze cone cups (used to be 2-046 but this code is now something else) don't seem to offer much in combination with any axle that I have tried, but I have only seated them loosely and it may be worth fitting them in properly and gluing them. NOTE I have known one person receive one of these with a chassis which was basically broken and had substantial details missing. If something like this this happens to you please let me know, and let Shapeways know too; I'm sure they will refund you. It prints up pretty nicely in my experience. I have only ever had one which was a bit weak, and even that was still worth making up. UPDATE 11TH JULY 2015. I have made about a dozen of these now and in the last batch I found you can use Peco 8-spoke N-gauge wheels if you drill the wax out of the axleboxes a bit at a time until they fit, then run them in by pushing them back and forth (gently does it) on the cutting mat with a small weight on top. WIN!
UPDATE see my P22 brake levers model if you don't mind spending the extra to save the hassle of making them yourself from plastic rod and things in the bits box.