Coupler Size: Prototype and Model, by Bruce A. Metcalf

Conclusions and References

Perhaps if enough modelers take the ideas in this paper to heart and start using model couplers in scales for which they were not designed, and if users contact the companies with requests, they may consider producing some of their coupler models with different trip pin lengths. It could happen … that's how the Kadee ¾HO coupler was developed from the HOn3 model!

I would encourage further study of this topic using coupler body size as the reference (rather than knuckle height as I used) to see if my selection of knuckle height as the size reference holds up. However, I believe that most model couplers have a body-to-knuckle size ratio that is close enough to the prototype's that such a study would produce substantially the same results. Whether I have convinced you to change the size of couplers you use on your models or not, I hope I have challenged you to think of couplers as models, and given you enough information about the prototypes we are trying to model to give model couplers more serious consideration.

References:

Accurail Inc. Welcome to Accurail Inc. Internet web site.

Edwards, Dale (Kadee founder and owner). Telephone interview, 21 February 1994.

Engle, Coni. Micro-Trains Line press release, 22 February 1994.

Johnson, Bob. "AAR Coupler Contour." NMRA Data Sheets #D9p, November 1966.

Kadee Quality Products Co. Kadee Home Page. Internet web site.

McHenry Couplers. McHenry Couplers. Internet web site.

Metcalf, Bruce. "Model Railroad Benchwork: Evolution and Innovation in Design," in Larry Kline, editor, The Columbus Clinics, Kalmbach Memorial Library, 1992, pp. 33-41.

---. "Scale and Gauge: A Response," in NMRA Bulletin, October 1991, p. 40.

Micro-Trains Line Co. Micro-Trains Official Website. Internet web site.

National Model Railroad Association (NMRA). "General." NMRA Standard S-1, July 1988.

---. "Module Standards: Narrow Gauge." NMRA Standard MS-1.1, January 1990.

---. "Solid Couplers." NMRA Standard S-6, revised July 1954 (reclassified as RP-21.2 in 1957).

---. "Solid Couplers." NMRA Recommended Practice RP-21.2, revised February 1960.

Simmons-Boardman Publishing Corp. Car Builders' Cyclopedia, 13th edition, 1931, pp. 881-884.

---. Car Buiders' Cyclopedia, 14th edition, 1937, pp. 1003-1005.

---. Car Buiders' Cyclopedia, 20th edition, 1957, pp. 676-687.

Smith, Eric. Micro-Trains Line, correspondence, 22 February 1994.

Storzek, Dennis. Accurail, correspondence, 24 February 2000.