Proto:87

Proto:87
Scale	3.5 mm to 1 foot
Scale ratio	1:87.1
Standard(s)	Proto:87[1]
Model gauge	16.5 mm (0.65 in)[2]
Prototype gauge	1435 mm (4 ft 8+1⁄2 in) standard gauge

Proto:87 is a set of model railroad engineering standards that resulted from a special interest group of that name founded in 1978, providing a fine-scale alternative to traditional HO scale.

Two trucks set to the same gauge: the one on the left has wheels made to Proto:87 standards and on the right the wheels are made to much coarser NMRA RP25 (code 110) standards

Due to manufacturing restrictions and considerations such as durability, ease of operation and price, most model railroad products feature significant compromises that inhibit their viability as accurate scale models of their prototypes. The most visible of these are wheels and track, which can be significantly thicker than the prototype. The desirability of realistic wheel dimensions among some modelers helped spawn the Proto:87 movement, which is backed by many manufacturers such as Northwest Short Line.^[3]

Proto:87 has its own online store that offers various components and kits to help correct these scale inaccuracies, such as kits for assembling accurate, to-scale trackwork and switches, finescale wheels for locomotives and rolling stock, etc.

Similarly, the Proto:48 group is dedicated to finescale modeling in O scale.^[4]

See also

• Rail transport modelling scales
• Model railway scales

References

1. "Home". proto87.org.
2. "Archived copy". Archived from the original on 2007-09-19. Retrieved 2013-07-07.
3. Coleman, Matt (2008). The Model Railroader's Guide to Logging Railroads. Kalmbach Publishing, Co. p. 76. ISBN 978-0-89024-702-0.
4. Volhard, Jim (1999). Maintaining and Repairing Your Scale Model Trains. Kalmbach Publishing, Co. p. 44. ISBN 978-0-89024-324-4.

External links

• Proto:87 SIG Official website
• Club Proto 87 (in French)
• Proto:87 International Team (in French)