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Official NMRA Recommended Practices
- The RECOMMENDED PRACTICE category was established by the NMRA Board of Trustees in January 1957, to:
- a. Promote maximum interchange between and within units.
- b. Specify the details of major components to improve design and function. 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 reason is permissible.
| Sheet No. | Title | Issue Date |
|---|---|---|
| RP-1 | Abbreviations | Jan. 1957 |
| RP-2 | NMRA STANDARDS Gauge | Aug. 1987 |
| RP-3 | Fine Scale - Track Deleted | Jan. 1990 |
| RP-4 | Fine Scale - Wheels Deleted | Jan. 1990 |
| RP-3.5 | Hi-Rail - Track Deleted | July 1982 |
| RP-4.5 | Hi-Rail - Wheels Deleted | Jan. 1990 |
| RP-5 | Electric Traction - General (With Proposals for Member Comment) | Proposed July 1986 |
| RP-5.1 | Electric Traction - Trolley Wire Frogs | Feb. 1982 |
| RP-5.2 | Electric Traction - Curvature & Drawbars | Feb. 1982 |
| RP-8 | Three-Point Track Gauges | Mar. 1983 |
| RP-9 | Electrical | May 1973 |
| RP-10 | Trackwork - General | June 1981 |
| RP-11 | Curvature and Rolling Stock | Jan. 1990 |
| RP-12 | Turnouts - General | Feb. 1961 |
| RP-12.1 | Turnout Dimensions - 0 Scale | Feb. 1961 |
| RP-12.2 | Turnout Dimensions - S Scale | Feb. 1961 |
| RP-12.3 | Turnout Dimensions - HO Scale | Feb. 1961 |
| RP 12.4 | Turnout Dimensions - OO & On3 Scales | Feb. 1961 |
| RP-12.5 | Turnout Dimensions - TT Scale | Feb. 1961 |
| RP-12.6 | Turnout Dimensions - HOn3 Scale | Feb. 1961 |
| RP-12.7 | Turnout Dimensions - N Scale | Dec. 1979 |
| RP-13.5 | Guard Rail & Frog Relationship | Aug. 1981 |
| RP-13.6 | Guard Rails | Aug. 1981 |
| RP-13.7 | Frog & Wing Rails | Aug. 1981 |
| RP-13.8 | Flangeway Flares | Aug. 1981 |
| RP-15.1 | Rail | Jan. 1990 |
| RP-20.1 | Car Weight | Jan. 1990 |
| RP-21.1 | Coupler Contour | Aug. 1957 |
| RP-21.2 | Solid Couplers | Feb. 1960 |
| RP-22 | Coupler Pocket - HO Scale | Aug. 1958 |
| RP-23 | Bolsters | Aug. 1961 |
| RP-24 | Trucks | Aug. 1963 |
| RP-24.1 | Journals | July 1982 |
| RP-24.2 | Wheelsets | Aug. 1963 |
| RP-24.3 | Axles | July 1982 |
| RP-25 | Wheel Contour | Mar. 1997 |
| RP-37 | Locomotive/Tender -Drawbar & Pin Relationship | Mar. 1997 |
| RP-37.1 | Locomotive/Tender -Drawbar & Pin Dimensions | Mar. 1997 |
THE NATIONAL MODEL RAILROAD ASSOCIATION, INC.
4121 Cromwell Road, Chattanooga, TN 37421
Permission to reproduce this copyrighted publication in whole or in part may be obtained upon written application to the chattanooga office of NMRA.