@PRR1950 posted:I think I remember reading somewhere (so, don't quote me!!) that O scale in England was (and may still be) 1:43.5 scale. Thus, when Half-O was created (1/2 x 1/43.5), it came to 1:87. On the European continent, 1:87 translated to 3.5mm gauge and O translated to 7mm gauge. Also, if I remember correctly, in HO there is no difference between the scale size of pieces and track width (gauge), so the Proto87 guys are only worried about oversize flanges, oversized couplers, and other accoutrements that are intentionally oversized for ease of modeling and use.
Chuck
That’s correct. European O Gauge was, and still is 1:43.5, 7mm/ft on 32mm or 33mm Gauge Track. HO was, and still is half of that, 1:87, 3.5mm/ft on 16.5mm Gauge Track. British HO never really established itself, and British OO became standardised at 1:76, 4mm/ft on 16.5mm Gauge because of various practical aspects of making models of British outline locomotives and stock.
For various reasons, when modelling British outline it’s easier to be under-Gauge relative to scale, whereas for American outline stock it’s easier to be over-gauge relative to scale.
