British two rail is truly O scale too for standard gauge track at 4'-8 1/2" between the rails at 1:43.5. In the US our two and three rail is wide gauge at 5' between the rails at 1:48. Starting the 30's there was a movement to standarize US two rail O as 17/64" scale but 1/4" scale won out in the end. Many of those locomotives and cars are highly sought out by people who know what they are looking for.
To confuse things further, talk to a Proto-48 modeler 
Love the pictures. Very nice modeling and layouts from the other "side of the pond".
