3D-printer Files

The NASG web site is a central location where those who model in S can learn and share their knowledge. With that in mind, in January 2026 we launched the ability for S modelers, who enjoy designing 3D CAD models for the purpose of printing those models using 3D-printers, to share those files with other S modelers, if they so choose.

Designers

We will only list those designs for which the owner/designer is willing to share the files for no fee. If the owner/designer wants or needs to charge a fee for the files, we recommend using one of the many commercial web sites.

To manage these files, the NASG webmaster will take receipt of the files the owner/designer is willing to share with others on this public web site, and organize them in a manner where they can be easily found and accessed by fellow S modelers. So, if you are willing to share one or more files, please contact the webmaster: webmaster@nasg.org.

Users

These files are copyrighted and are intellectual property materials, some of which the owner has commissioned a designer to create for them at personal expense. Or the owner/designer is him- or herself a CAD designer, investing many hours in the perfection of the design.

These files are shared in good faith, so please observe and honor the owner/designer's license agreement under which they are willing to share the files. If you have a 3D-printer or have access to a 3D-printer, feel free to download the files of interest.

The Files

• Freight Car Parts (entries: 4)
• Locomotive Parts (entries: 2)
• Tender Parts (entries: 1)
• Track (entries: 6)

Introduction

3D-printing is a powerful method for creating some physical item from a CAD (computer-aided design) drawing. A CAD designer creates a complete 3D model in the virtual world of the computer.

When the design is complete, it is exported into a standard file format called "STL", a file extension originally based on the name "stereolithography", but is now called "standard triangle language". An stl file holds a collection of triangles defined in the three-dimensional Cartesian coordinate system. These triangles approximate the curves laid out in the original CAD drawing. The more triangles, the more accurate the approximation to the original CAD design, but the larger the .stl file will be. While the .stl file can have the triangles defined in plaintext ASCII, it is typically exported in a binary format which significantly reduces the resultant file size. For complex designs, these files can be quite large. The .stl file is independent of which CAD program the designer used to create the original design. These .stl files are the ones that are shared in the files listing, above.

The .stl file is a common standard file, but to actually print the content of that file, a software application needs to be used to convert that file into individual instructions for the 3D-printer you will be using to print that file. Most 3D-printer manufacturers have a software application that allows you to import the .stl file and prepare the design for actual printing. Third-party "slicer" programs are also available for that purpose. When that step is finished, the final printer-instructions file is saved to some sort of a memory card (e.g. microSD), if your 3D-printer is located elsewhere, or sent to the printer, if it is connected directly to your PC or via a local-area-network connection.