Even I faced these challenges. These models are intellectual properties of some company or creator & you will have to improvise if you need the CAD models that badly. They will never be as perfect as the original blueprints from EMD or GE, but you could get it close enough for a 1:48 scale model.
Here is an example of what I did to get 2-D CAD data. I used to have favorite European electric locomotive when I was in HO scale – Siemens ES64F4, in the colors of the leasing company, Mitsui Rail (MRCE), shown below.
When I moved to O-Scale, I greatly missed not having it available. So I collected a lot of photos & scanned raster images of this book.
I also found a pdf brochure of MRCE, saved the front page, shown below, as a JPEG.
I then imported the image into AutoCAD & over the next several months, mainly on evenings & weekends, I traced lines & curves over every pixel. I used my HO model & the photos to resolve any blurred areas in the raster file & to also make sure that my assumptions weren’t too far from reality.
Since the image was just of 1 side, based on dimensions from the Siemens mobility website, I scaled & mirrored the ends.
I still haven’t completed the center portion yet but I have what I need should I choose to complete it.
These are just my opinion,
Thanks,
Naveen Rajan
One big issue that's preventing me from making things is that people generally aren't willing to share their drawing files or sources for the dimensions....
Trevor
Well you've just identified the number one problem, finding accurate data to start from. I've been after technical info for EMD htc-1 trucks for years so I could accurately model them in 3d cad. EMD claims not to have drawings (bs!) and search after search of the internet yields almost nothing.
Scaling an existing 3d model to go from HO to O scale in my opinion is about a 30 second exercise. It's either done in the cad file before it's exported to .stl, or the scale factor can be set in the printer software when the tool paths are created. Either way the only real concern is layer or wall thicknesses based on the capabilities of the printer being used. Going bigger shouldn't present much of a problem. That's the beauty of 3d printing. The same model can easily create output in multiple scales without any of the additional tooling required for the same results with injection molding.
I can't really fault people for keeping their 3d data close to the vest. Information sources aren't quite so proprietary, but if the information is a result of a lot of field research, then that is significant time invested. The multiscale capability of 3d printing is concurrently a disincentive for open cooperation. By default you are a competitor because I can make my product for any market. It's not quite like striking an agreement with Athearn to share r&d data with them producing for the N and HO markets and you producing only for the O market.
All that being said, I feel your pain. Rebel Locomotives on Shapeways (nee Railflyer) has a lot of great cad work for diesel parts, including my coveted htc-1 sideframes and traction motor housings. He got the information from somewhere, but I wouldn't expect him to offer it to me for free.
And there actually are plenty of sources of technical data available. It's just a matter of finding it. Car and Locomotive Cyclopedias have tons of prototype data in them, including beautiful drawings of the EMD Blomberg sideframe. Kalmbach publishes diesel and steam cylcopedias that have varying levels of accurate line drawings for locomotives. And in my case they were available at the local library. Many manufacturers and railroads have technical data available on their websites. And print magazines often feature technical drawings, or at least they used to. Mainline Modeler in particular featured drawings all the time. Older Model Railroader often had prototype drawings. RMC did and still does feature a fair amount of prototype drawings. So the info is frequently out there somewhere, but not always.
Jim
