[2] The best-known activity of the NMRA is the defining of standards, and advisory documents known as Recommended Practices (RP), for model railroad equipment in North America.

[citation needed] In Europe, the Normen Europäischer Modellbahnen (NEM) has the same role, and although there is fairly close cooperation between the two organisations the standards differ in some aspects.

At times this results in some models not working as intended on layouts that mix European and American rolling stock and trackwork.

Of note, the organization provides indirect assistance to the Boy Scouts of America's Railroading Merit badge program by encouraging members (through a hierarchy of National and Regional volunteer Boy Scout Coordinators) to become Railroading Merit Badge Counselors.

[4] The library was adjacent to the Norfolk Southern Railway Georgia Division and the Tennessee Valley Railroad Museum.