model railroad scale equivalents

Thanks guys, I see that I will need to be very careful in this.

Railway scales can be a mix of metric and Imperial, which leads to all sorts of confusion. The standard "OO" gauge is 4mm to the inch, or 1/76 scale, while "O" gauge is 7mm to the inch, and 1/43 scale. Gauge 1 is normally 1/32 scale (probably why kit manufacturers started producing what, at first glance, seems an odd scale.)

The problem I've found is that, for example, 1/48 from one company can be noticeably larger or smaller than 1/48 from another company. Enough of a difference that they would look strange in a diorama together.

O Scale (0 or Zero gauge) generally accepted as 1/48  scale, but items vary between 1/43  to 1/50 scale.

HO Scale (one Half of O) is 1/87 scale.

N Scale is 1/160 scale (Nine MM rail spacing)

G Gauge (AKA Gauge 1 or LGB) has a wide range of scales; most common are 1/20.3, 1/22.5, 1/24, 1/29, and. 1/32

This thread on another forum is useful 

http://www.kitmaker.net/modules.php?op=modload&name=SquawkBox&file=index&req=viewtopic&topic_id=98196&page=1