Pete wrote:I think, UK N is half OO scale not 160th as continental N.
Not quite. Half British OO gauge which is 4mm scale would be 2mm scale and that scale ratio is 1:152 not the 1:148 of British N gauge.
The reason it's different is because our real locos are smaller than continental and American locos and when the scale/gauge (1:160/9mm) was invented the smallest motors would not fit in a same scale British loco so it had to be made slightly larger at 1:148 plus there is an issue with the outside cylinders.
The family of N gauge/scales all running on 9mm gauge track are
* American and Continental 1:160 (1.9mm to 1ft)
* Japanese (and professional architecture) 1:150 (2.03mm to 1ft)
* British 1:148 (2.06mm to 1ft)
2mm fine scale (OOO) is 1:152 (2mm to 1ft) running on 9.4mm track.
G.