Standards and related reference information is available for all modelers and manufacturers using the website.  Membership is not required to access this information.  Below is a listing of the types of documents maintained:

Standards (S) and Recommended Practices (RP), Technical Notes (TN), and Technical Information (TI).

STANDARDS category is considered mandatory for acceptable interoperability.

RECOMMENDED PRACTICE category was established by the NMRA Board of Trustees in January 1957, to:

  • Specify the details of major components to improve design and function.
  • Promote maximum interchange between and within units.

RECOMMENDED PRACTICES are only less mandatory than STANDARDS by virtue of their slightly less critical subject matter and/or the fact that deviation for specific reasons is permissible.

TECHNICAL NOTES and TECHNICAL INFORMATION provided added and detailed information that the user can read to gain more detailed information on the given subject.

The NMRA information is maintained on the website. will access additional background information. will access the listing and links to all NMRA Standards and technical documents.

NMRA technical documents are open to update and improvements.  O Scale Central will assist.

Drafted 3 12 2023 by Eric Peterson