Scale 3.5 mm to 1 foot Standard(s) Proto:87 | Scale ratio 1:87.1 Model gauge 16.5 mm (0.65 in) | |
Prototype gauge 1,435 mm (4 ft 8 ⁄2 in) standard gauge | ||
Proto:87 is a model railroad special interest group founded in 1978, dedicated to providing a finescale alternative to traditional HO scale.
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.
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.