In the Spring issue of BRM, I've started a series of micro layouts designed to fit on the shelves of an Ikea Billy Bookcase.   There will be three layouts - OO, 009 and N   I'm keen to build an N gauge model to see how the smaller scale makes better use of the space. In theory, we ought to be able to fit a lot more model on the shelf than in the larger scales, but I don't want something crammed with trackwork.   So, I'm throwing down a challenge to N gauge modellers